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A114312
Number of partitions of n with at most 3 odd parts.
1
1, 1, 2, 3, 4, 6, 8, 12, 14, 22, 24, 38, 39, 63, 62, 102, 95, 159, 144, 244, 212, 366, 309, 540, 442, 784, 626, 1125, 873, 1591, 1209, 2229, 1653, 3089, 2245, 4243, 3019, 5776, 4035, 7806, 5348, 10466, 7051, 13944, 9229, 18454, 12022, 24282, 15565, 31766, 20063
OFFSET
0,3
LINKS
FORMULA
G.f.: (1+x/(1-x^2)+x^2/(1-x^2)/(1-x^4)+x^3/(1-x^2)/(1-x^4)/(1-x^6))/Product(1-x^(2*i), i=1..infinity).
EXAMPLE
a(6) = 8 because we have 6, 51, 42, 411, 33, 321, 222 and 2211 (3111, 21111 and 111111 do not qualify).
MAPLE
G:=(1+x/(1-x^2)+x^2/(1-x^2)/(1-x^4)+x^3/(1-x^2)/(1-x^4)/(1-x^6))/Product(1-x^(2*i), i=1..100): Gser:=series(G, x, 70): seq(coeff(Gser, x, n), n=0..60);
MATHEMATICA
nmax = 50; CoefficientList[Series[(1+x/(1-x^2)+x^2/(1-x^2)/(1-x^4)+x^3/(1-x^2)/(1-x^4)/(1-x^6)) * Product[1/(1-x^(2*k)), {k, 1, nmax}], {x, 0, nmax}], x] (* Vaclav Kotesovec, Mar 07 2016 *)
CROSSREFS
Sequence in context: A101902 A236912 A215966 * A095041 A331088 A336506
KEYWORD
nonn
AUTHOR
Emeric Deutsch, Feb 05 2006
STATUS
approved