A039828 Largest coefficient in expansion of Product_{i=1..n} (1 + (-q)^i).

1, 1, 1, 2, 3, 5, 8, 14, 23, 40, 69, 123, 221, 397, 722, 1314, 2410, 4441, 8215, 15260, 28460, 53222, 99820, 187692, 353743, 668273, 1264854, 2399207, 4559828, 8679280, 16547220, 31592878, 60400688, 115633260, 221625505, 425313967

Offset

1,4

Links

Seiichi Manyama, Table of n, a(n) for n = 1..1000

Formula

a(n) ~ sqrt(3) * 2^(n + 1/2) / (sqrt(Pi) * n^(3/2)). - Vaclav Kotesovec, Feb 04 2022

Prog

(PARI) a(n) = vecmax(Vec(prod(i = 1, n, (1 + (-q)^i)))); \\ Michel Marcus, Aug 30 2018

Crossrefs

Cf. A025591, A039829.

Sequence in context: A191317 A218020 A318520 * A357303 A246360 A005627

Adjacent sequences: A039825 A039826 A039827 * A039829 A039830 A039831

Keyword

nonn

Author

Olivier Gérard

Status

approved