A104886 Sequence A048138, the number of times that a positive integer occurs as the sum of proper divisors, if Goldbach partitions (two odd primes, which account for most of the values) are ignored.

0, 1, 1, 0, 2, 1, 2, 0, 1, 0, 1, 1, 2, 1, 2, 0, 1, 0, 2, 1, 2, 0, 1, 0, 1, 0, 1, 0, 1, 2, 2, 1, 1, 0, 1, 0, 1, 0, 3, 1, 2, 1, 2, 0, 2, 0, 1, 1, 2, 0, 0, 0, 2, 1, 1, 2, 1, 0, 1, 0, 2, 1, 3, 1, 1, 0, 1, 0, 1, 0, 1, 2, 3, 0, 3, 0, 1, 0, 1, 2, 1, 0, 1, 0, 1, 1, 0, 1, 2, 0, 2, 0, 1, 0, 0, 2

Offset

2,5

Links

Table of n, a(n) for n=2..97.

Formula

a(n) = number of m such that the sum of the proper divisors of m is n, ignoring m if m is the product of two different odd primes.

Example

a(13)=1 because s(27)=1+3+9 and s(35)=1+5+7=13 however 35's factors 3 and 5 are a Goldbach partition, so 35 is not counted.

Crossrefs

Cf. A048138, A001065, A061358.

Sequence in context: A070088 A131851 A345021 * A215604 A139351 A285677

Adjacent sequences: A104883 A104884 A104885 * A104887 A104888 A104889

Keyword

nonn

Author

Nathan McNew (agreatnate(AT)yahoo.com), Mar 29 2005

Status

approved