Concept information
Preferred term
almost perfect number
Definition
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In mathematics, an almost perfect number (sometimes also called slightly defective or least deficient number) is a natural number n such that the sum of all divisors of n (the sum-of-divisors function σ(n)) is equal to 2n − 1, the sum of all proper divisors of n, s(n) = σ(n) − n, then being equal to n − 1. The only known almost perfect numbers are powers of 2 with non-negative exponents (sequence A000079 in the OEIS).
(Wikipedia, The Free Encyclopedia, https://en.wikipedia.org/wiki/Almost_perfect_number)
Broader concept
Entry terms
- least deficient number
- slightly defective number
In other languages
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French
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nombre légèrement déficient
URI
http://data.loterre.fr/ark:/67375/PSR-CVV396PH-P
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