OFFSET
1,2
LINKS
Amiram Eldar, Table of n, a(n) for n = 1..10000
Eric Weisstein's World of Mathematics, Deficient Number
Eric Weisstein's World of Mathematics, Partition
MATHEMATICA
n = 60; d = Select[Range[n], DivisorSigma[1, #] < 2 # &]; CoefficientList[ Series[1/Product[1 - x^d[[i]], {i, 1, Length[d]}], {x, 0, n}], x][[d + 1]] (* Amiram Eldar, Aug 02 2019 *)
CROSSREFS
KEYWORD
nonn
AUTHOR
Reinhard Zumkeller, Aug 25 2004
STATUS
approved