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A329163 Expansion of Product_{k>=1} 1 / (1 - Sum_{j>=1} j * x^(j*(2*k - 1))). 1
1, 1, 3, 9, 22, 59, 156, 405, 1061, 2786, 7284, 19071, 49948, 130738, 342288, 896175, 2346134, 6142287, 16080852, 42100020, 110219366, 288558380, 755455128, 1977807393, 5177967900, 13556094631, 35490316938, 92914858431, 243254253904, 636847905903, 1667289469704, 4365020491362 (list; graph; refs; listen; history; text; internal format)
OFFSET
0,3
COMMENTS
Weigh transform of A032198.
LINKS
FORMULA
G.f.: Product_{k>=1} 1 / (1 - x^(2*k - 1) / (1 - x^(2*k - 1))^2).
G.f.: Product_{k>=1} (1 + x^k)^A032198(k).
a(n) ~ c * phi^(2*n) / sqrt(5), where c = Product_{k>=2} 1/(1 - phi^(2 - 4*k)/(phi^(2 - 4*k) - 1)^2) = 1.07705428718361459418304978675229012... and phi = A001622 = (1+sqrt(5))/2 is the golden ratio. - Vaclav Kotesovec, Nov 07 2019
MATHEMATICA
nmax = 31; CoefficientList[Series[Product[1/(1 - Sum[j x^(j (2 k - 1)), {j, 1, nmax}]), {k, 1, nmax}], {x, 0, nmax}], x]
nmax = 31; CoefficientList[Series[Product[1/(1 - x^(2 k - 1)/(1 - x^(2 k - 1))^2), {k, 1, nmax}], {x, 0, nmax}], x]
CROSSREFS
Sequence in context: A192663 A114697 A032284 * A296582 A203454 A197666
KEYWORD
nonn
AUTHOR
Ilya Gutkovskiy, Nov 06 2019
STATUS
approved

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Last modified March 4 22:06 EST 2024. Contains 370532 sequences. (Running on oeis4.)