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A252891
Numbers n such that sigma(n) is a partition number.
2
1, 2, 4, 8, 20, 26, 28, 29, 39, 41, 129, 430, 526, 591, 655, 731, 1388, 1622, 2249, 3734, 6841, 18752, 18772, 21332, 35017, 37337, 53173, 105557, 113377, 124753, 419029, 614153, 824149, 829333, 2192923, 2369654, 2538915, 3059853, 3388115, 3479244, 3557183
OFFSET
1,2
LINKS
Robert G. Wilson v, Table of n, a(n) for n = 1..65
EXAMPLE
26 is in the sequence because the sum of divisors of 26 is 1 + 2 + 13 + 26 = 42 and 42 is a partition number because the number of partitions of 10 is equal to 42.
MATHEMATICA
(* To extend the search beyond 50400, be sure to increase the length of partNums accordingly *) partNums = PartionsP[Range[50]]; Select[Range[100], MemberQ[partNums, DivisorSigma[1, #]] &] (* Alonso del Arte, Dec 24 2014 *)
CROSSREFS
Sequence in context: A124154 A296606 A222562 * A102634 A026520 A282983
KEYWORD
nonn
AUTHOR
Omar E. Pol, Dec 24 2014
EXTENSIONS
a(11)-a(16) from Alonso del Arte, Dec 24 2014
More terms from Michel Marcus, Dec 27 2014
STATUS
approved