A371547 Expansion of e.g.f. Product_{k>=1} 1 / (1 - 2*x^k/k).

1, 2, 10, 64, 548, 5608, 68936, 973600, 15700352, 283559424, 5685644928, 125227712256, 3007981305600, 78237291643392, 2191215982262784, 65744691667064832, 2103999919044163584, 71538799576401408000, 2575460412946013810688, 97868678834373255069696, 3914776163575281528889344

Offset

0,2

Links

Table of n, a(n) for n=0..20.

Formula

a(n) ~ c * 2^n * n!, where c = Product_{k>=2} 1/(1 - 2^(1-k)/k) = 1.5345676172355916355224667976662106649465582052467986508967405417359... - Vaclav Kotesovec, Mar 28 2024

Mathematica

nmax = 20; CoefficientList[Series[Product[1/(1 - 2 x^k/k), {k, 1, nmax}], {x, 0, nmax}], x] Range[0, nmax]!

Crossrefs

Cf. A007841, A371546, A371548.

Sequence in context: A361407 A323666 A318814 * A130721 A167449 A064170

Adjacent sequences: A371544 A371545 A371546 * A371548 A371549 A371550

Keyword

nonn

Author

Ilya Gutkovskiy, Mar 27 2024

Status

approved