login
A397057
Convolution of A000203 and A156616.
2
0, 1, 5, 16, 49, 130, 332, 792, 1825, 4049, 8726, 18320, 37620, 75682, 149564, 290788, 557017, 1052590, 1964353, 3623568, 6612698, 11946904, 21381720, 37930772, 66730680, 116478135, 201805078, 347179864, 593284716, 1007389494, 1700141724, 2852620740, 4759740593, 7899577736, 13043665078
OFFSET
0,3
COMMENTS
Convolution of A276432 and A026007.
Convolution of A397056 and A000219.
LINKS
FORMULA
G.f.: Sum_{j>=1} (j*x^j/(1-x^j)) * Product_{k>=1} ((1+x^k)/(1-x^k))^k.
a(n) ~ Pi^(3/2) * exp(1/12 + 3*(7*zeta(3))^(1/3)*n^(2/3)/2^(4/3)) / (A * 2^(10/9) * 3^(3/2) * (7*zeta(3))^(17/36) * n^(1/36)), where A is the Glaisher-Kinkelin constant A074962.
MATHEMATICA
nmax = 50; CoefficientList[Series[Sum[j*x^j/(1-x^j), {j, 1, nmax}] * Product[((1+x^k)/(1-x^k))^k, {k, 1, nmax}], {x, 0, nmax}], x]
CROSSREFS
KEYWORD
nonn
AUTHOR
Vaclav Kotesovec, Jun 15 2026
STATUS
approved