A306730 Expansion of Sum_{k>=0} x^k * Product_{j=1..k} (1 + j*x^j).

1, 1, 2, 2, 4, 6, 9, 12, 22, 32, 45, 70, 98, 153, 231, 318, 452, 685, 933, 1387, 1988, 2769, 3850, 5433, 7622, 10530, 14896, 20635, 28123, 38934, 53067, 72144, 99509, 133661, 183794, 249130, 333956, 448306, 605165, 807053, 1078093, 1444021, 1913418, 2556415, 3406636

Offset

0,3

Links

Table of n, a(n) for n=0..44.

Mathematica

nmax = 44; CoefficientList[Series[Sum[x^k Product[(1 + j x^j), {j, 1, k}], {k, 0, nmax}], {x, 0, nmax}], x]

Crossrefs

Cf. A000009, A193196, A306702.

Sequence in context: A240065 A237755 A362260 * A209603 A192684 A274147

Adjacent sequences: A306727 A306728 A306729 * A306731 A306732 A306733

Keyword

nonn

Author

Ilya Gutkovskiy, Mar 06 2019

Status

approved