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A035940
Number of partitions in parts not of the form 9k, 9k+1 or 9k-1. Also number of partitions with no part of size 1 and differences between parts at distance 3 are greater than 1.
1
0, 1, 1, 2, 2, 4, 4, 6, 7, 10, 12, 17, 19, 26, 31, 40, 47, 61, 71, 90, 106, 131, 154, 190, 222, 270, 317, 381, 445, 533, 620, 737, 857, 1011, 1173, 1379, 1593, 1863, 2151, 2503, 2881, 3343, 3837, 4435, 5083, 5853, 6693, 7688, 8769, 10043, 11437, 13061
OFFSET
1,4
COMMENTS
Case k=4, i=1 of Gordon Theorem.
REFERENCES
G. E. Andrews, The Theory of Partitions, Addison-Wesley, 1976, p. 109.
FORMULA
a(n) ~ exp(2*Pi*sqrt(n)/3) / (6 * (1+2*cos(2*Pi/9)) * n^(3/4)). - Vaclav Kotesovec, Nov 12 2015
MAPLE
# See A035937 for GordonsTheorem
A035940_list := n -> GordonsTheorem([0, 1, 1, 1, 1, 1, 1, 0, 0], n):
A035940_list(40) # Peter Luschny, Jan 22 2012
MATHEMATICA
nmax = 60; Rest[CoefficientList[Series[Product[1 / ((1 - x^(9*k-2)) * (1 - x^(9*k-3)) * (1 - x^(9*k-4)) * (1 - x^(9*k-5)) * (1 - x^(9*k-6)) * (1 - x^(9*k-7)) ), {k, 1, nmax}], {x, 0, nmax}], x]] (* Vaclav Kotesovec, Nov 12 2015 *)
PROG
(Sage) # See A035937 for GordonsTheorem
def A035940_list(len) : return GordonsTheorem([0, 1, 1, 1, 1, 1, 1, 0, 0], len)
A035940_list(40) # Peter Luschny, Jan 22 2012
CROSSREFS
Sequence in context: A001996 A317084 A122134 * A067772 A078374 A366129
KEYWORD
nonn,easy
STATUS
approved