15 (fifteen) is the natural number following 14 and preceding 16.Template:Infobox number

MathematicsEdit

File:Chord diagrams K6 matchings.svg
The 15 perfect matchings of K6
File:15-square-difference.png
15 as the difference of two positive squares (in orange).

15 is:

|CitationClass=web }}</ref> a hexagonal number,<ref>Template:Cite OEIS</ref> and pentadecagonal number.<ref>Template:Cite OEIS</ref>

Furthermore,

2, 3, 5, 7, 23, 37, 53, 73, 313, 317, 373, 797, 3137, 3797, 739397 (sequence A020994 in the OEIS)

ReligionEdit

SunnismEdit

The Hanbali Sunni madhab states that the age of fifteen of a solar or lunar calendar is when one's taklif (obligation or responsibility) begins and is the stage whereby one has his deeds recorded.<ref>Template:Cite book</ref>

JudaismEdit

ReferencesEdit

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Further readingEdit

External linksEdit

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  • {{#invoke:citation/CS1|citation

|CitationClass=web }} – discussing hexadecimals

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|CitationClass=web }} – discussing the Celtic number as used in Lincolnshire

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