A269155 Expansion of Product_{k>=1} (1 - k*x^k)/(1 + 2*x^k).

1, -3, 2, -5, 17, -23, 43, -87, 178, -378, 700, -1402, 2837, -5651, 11295, -22592, 45397, -90587, 181187, -362566, 724949, -1449986, 2900068, -5801059, 11601675, -23204798, 46409816, -92817126, 185633688, -371270603, 742544062, -1485079884, 2970162411

Offset

0,2

Links

Vaclav Kotesovec, Table of n, a(n) for n = 0..3300

Formula

a(n) ~ c * (-2)^n, where c = Product_{k>=1} ((-2)^k - k)/((-2)^k - 1) = 0.691544539061740396647761051109300225267201237557458470928297389967...

Mathematica

nmax = 50; CoefficientList[Series[Product[(1-k*x^k)/(1+2*x^k), {k, 1, nmax}], {x, 0, nmax}], x]

Crossrefs

Cf. A269144, A269153, A269154.

Sequence in context: A214502 A077039 A374834 * A103938 A304534 A085973

Adjacent sequences: A269152 A269153 A269154 * A269156 A269157 A269158

Keyword

sign

Author

Vaclav Kotesovec, Feb 20 2016

Status

approved