Hyperperfect number

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In number theory, a Template:Mvar-hyperperfect number is a natural number Template:Mvar for which the equality <math>n = 1+k(\sigma(n)-n-1)</math> holds, where Template:Math is the divisor function (i.e., the sum of all positive divisors of Template:Mvar). A hyperperfect number is a Template:Mvar-hyperperfect number for some integer Template:Mvar. Hyperperfect numbers generalize perfect numbers, which are 1-hyperperfect.<ref>{{#invoke:citation/CS1|citation |CitationClass=web }}</ref>

The first few numbers in the sequence of Template:Mvar-hyperperfect numbers are Template:Nowrap (sequence A034897 in the OEIS), with the corresponding values of Template:Mvar being Template:Nowrap (sequence A034898 in the OEIS). The first few Template:Mvar-hyperperfect numbers that are not perfect are Template:Nowrap (sequence A007592 in the OEIS).

List of hyperperfect numbersEdit

The following table lists the first few Template:Mvar-hyperperfect numbers for some values of Template:Mvar, together with the sequence number in the On-Line Encyclopedia of Integer Sequences (OEIS) of the sequence of Template:Mvar-hyperperfect numbers:

List of some known Template:Mvar-hyperperfect numbers
Template:Mvar Template:Mvar-hyperperfect numbers OEIS
1 6, 28, 496, 8128, 33550336, ... Template:OEIS2C
2 21, 2133, 19521, 176661, 129127041, ... Template:OEIS2C
3 325, ...  
4 1950625, 1220640625, ...  
6 301, 16513, 60110701, 1977225901, ... Template:OEIS2C
10 159841, ...  
11 10693, ...  
12 697, 2041, 1570153, 62722153, 10604156641, 13544168521, ... Template:OEIS2C
18 1333, 1909, 2469601, 893748277, ... Template:OEIS2C
19 51301, ...  
30 3901, 28600321, ...  
31 214273, ...  
35 306181, ...  
40 115788961, ...  
48 26977, 9560844577, ...  
59 1433701, ...  
60 24601, ...  
66 296341, ...  
75 2924101, ...  
78 486877, ...  
91 5199013, ...  
100 10509080401, ...  
108 275833, ...  
126 12161963773, ...  
132 96361, 130153, 495529, ...  
136 156276648817, ...  
138 46727970517, 51886178401, ...  
140 1118457481, ...  
168 250321, ...  
174 7744461466717, ...  
180 12211188308281, ...  
190 1167773821, ...  
192 163201, 137008036993, ...  
198 1564317613, ...  
206 626946794653, 54114833564509, ...  
222 348231627849277, ...  
228 391854937, 102744892633, 3710434289467, ...  
252 389593, 1218260233, ...  
276 72315968283289, ...  
282 8898807853477, ...  
296 444574821937, ...  
342 542413, 26199602893, ...  
348 66239465233897, ...  
350 140460782701, ...  
360 23911458481, ...  
366 808861, ...  
372 2469439417, ...  
396 8432772615433, ...  
402 8942902453, 813535908179653, ...  
408 1238906223697, ...  
414 8062678298557, ...  
430 124528653669661, ...  
438 6287557453, ...  
480 1324790832961, ...  
522 723378252872773, 106049331638192773, ...  
546 211125067071829, ...  
570 1345711391461, 5810517340434661, ...  
660 13786783637881, ...  
672 142718568339485377, ...  
684 154643791177, ...  
774 8695993590900027, ...  
810 5646270598021, ...  
814 31571188513, ...  
816 31571188513, ...  
820 1119337766869561, ...  
968 52335185632753, ...  
972 289085338292617, ...  
978 60246544949557, ...  
1050 64169172901, ...  
1410 80293806421, ...  
2772 95295817, 124035913, ... Template:OEIS2C
3918 61442077, 217033693, 12059549149, 60174845917, ...  
9222 404458477, 3426618541, 8983131757, 13027827181, ...  
9828 432373033, 2797540201, 3777981481, 13197765673, ...  
14280 848374801, 2324355601, 4390957201, 16498569361, ...  
23730 2288948341, 3102982261, 6861054901, 30897836341, ...  
31752 4660241041, 7220722321, 12994506001, 52929885457, 60771359377, ... Template:OEIS2C
55848 15166641361, 44783952721, 67623550801, ...  
67782 18407557741, 18444431149, 34939858669, ...  
92568 50611924273, 64781493169, 84213367729, ...  
100932 50969246953, 53192980777, 82145123113, ...  

It can be shown that if Template:Math is an odd integer and <math>p = \tfrac{3k+1}{2}</math> and <math>q = 3k+4</math> are prime numbers, then Template:Tmath is Template:Mvar-hyperperfect; Judson S. McCranie has conjectured in 2000 that all Template:Mvar-hyperperfect numbers for odd Template:Math are of this form, but the hypothesis has not been proven so far. Furthermore, it can be proven that if Template:Math are odd primes and Template:Mvar is an integer such that <math>k(p+q) = pq-1,</math> then Template:Mvar is Template:Mvar-hyperperfect.

It is also possible to show that if Template:Math and <math>p = k+1</math> is prime, then for all Template:Math such that <math>q = p^i - p+1</math> is prime, <math>n = p^{i-1}q</math> is Template:Mvar-hyperperfect. The following table lists known values of Template:Mvar and corresponding values of Template:Mvar for which Template:Mvar is Template:Mvar-hyperperfect:

Values of Template:Mvar for which Template:Mvar is Template:Mvar-hyperperfect
Template:Mvar Values of Template:Mvar OEIS
16 11, 21, 127, 149, 469, ... Template:OEIS2C
22 17, 61, 445, ...  
28 33, 89, 101, ...  
36 67, 95, 341, ...  
42 4, 6, 42, 64, 65, ... Template:OEIS2C
46 5, 11, 13, 53, 115, ... Template:OEIS2C
52 21, 173, ...  
58 11, 117, ...  
72 21, 49, ...  
88 9, 41, 51, 109, 483, ... Template:OEIS2C
96 6, 11, 34, ...  
100 3, 7, 9, 19, 29, 99, 145, ... Template:OEIS2C

ReferencesEdit

Template:Reflist

Further readingEdit

ArticlesEdit

BooksEdit

  • Daniel Minoli, Voice over MPLS, McGraw-Hill, New York, NY, 2002, Template:ISBN (p. 114-134)

External linksEdit

Template:Divisor classes Template:Classes of natural numbers