id:A048138 - OEIS Search Results

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a(n) = number of m such that sum of proper divisors of m (A001065(m)) is n.

+0
10

0, 1, 1, 0, 2, 1, 2, 1, 1, 1, 1, 2, 2, 2, 2, 2, 1, 2, 2, 3, 2, 2, 1, 3, 1, 2, 1, 2, 1, 5, 2, 3, 1, 3, 1, 4, 1, 1, 3, 4, 2, 5, 2, 3, 2, 3, 1, 6, 2, 4, 0, 3, 2, 6, 1, 5, 1, 3, 1, 6, 2, 3, 3, 6, 1, 6, 1, 2, 1, 5, 1, 8, 3, 4, 3, 5, 1, 7, 1, 6, 1, 4, 1, 8, 1, 5, 0, 5, 2, 9, 2, 4, 1, 4, 0, 9, 1, 3, 2, 6, 1, 8, 2, 7, 4 (list; graph; listen)

	OFFSET	`2,5`
	COMMENT	`The graph of this sequence, shifted by 1, looks similar to that of A061358, which counts Goldbach partitions of n. - T. D. Noe, Dec 05 2008`
	LINKS	`T. D. Noe, Table of n, a(n) for n=2..10000`
	EXAMPLE	`E.g. if n=6 then since s(25)=6, s(6)=6, a(6) = 2. The offset is 2 since there are infinitely many numbers (all the primes) for which A001065 = 1.`
	MAPLE	with(numtheory): for n from 2 to 150 do count := 0: for m from 1 to n^2 do if sigma(m) - m = n then count := count+1 fi: od: printf(`%d, `, count): od:
	CROSSREFS	`Cf. A001065, A005114, A064440.` `Sequence in context: A103414 A092400 A161895 this_sequence A165022 A030338 A159847` `Adjacent sequences: A048135 A048136 A048137 this_sequence A048139 A048140 A048141`
	KEYWORD	`easy,nonn`
	AUTHOR	`Naohiro Nomoto (6284968128(AT)geocities.co.jp)`
	EXTENSIONS	`More terms from James A. Sellers (sellersj(AT)math.psu.edu), Feb 19 2001`

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Last modified November 23 17:09 EST 2009. Contains 167438 sequences.

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