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A066920
Number of partitions of n into lucky parts.
0
1, 1, 2, 2, 2, 3, 4, 4, 6, 7, 7, 9, 11, 12, 15, 18, 19, 23, 26, 28, 34, 39, 42, 49, 56, 60, 69, 79, 85, 97, 110, 118, 133, 150, 162, 181, 203, 219, 243, 271, 292, 323, 359, 387, 425, 471, 507, 554, 612, 659, 719, 791, 851, 924, 1012, 1089, 1179, 1289, 1386, 1497, 1630
OFFSET
1,3
LINKS
V. Gardiner, R. Lazarus, N. Metropolis, and S. Ulam, On certain sequences of integers defined by sieves, Mathematics Magazine, 29(3) (1955), 117-122.
Eric Weisstein's World of Mathematics, Lucky number.
Wikipedia, Lucky number.
EXAMPLE
a(7) = 4 because we have the following partitions of n = 7 into lucky numbers: 7 = 3 + 3 + 1 = 3 + 1 + 1 + 1 + 1 = 1 + 1 + 1 + 1 + 1 + 1 + 1. - Petros Hadjicostas, Jun 05 2020
MATHEMATICA
lst = Range[1, 100, 2]; i = 2; While[ i <= (len = Length@lst) && (k = lst[[i]]) <= len, lst = Drop[lst, {k, len, k}]; i++ ]; Rest@ CoefficientList[Series[1/Times @@ (1 - x^lst), {x, 0, 61}], x] (* Robert G. Wilson v, May 12 2006 *)
CROSSREFS
Cf. A000959.
Sequence in context: A301337 A302404 A029050 * A035381 A096938 A130084
KEYWORD
easy,nonn
AUTHOR
Naohiro Nomoto, Jan 26 2002
EXTENSIONS
More terms from Robert G. Wilson v, May 12 2006
STATUS
approved