A306663 Expansion of Sum_{k>=0} x^(k*(k+1)) / Product_{j=1..k} (1 - j*x^j).

1, 0, 1, 1, 1, 1, 2, 2, 4, 4, 8, 8, 17, 17, 35, 38, 74, 80, 161, 173, 336, 387, 713, 818, 1555, 1765, 3248, 3923, 6905, 8282, 15012, 17814, 31419, 39321, 66679, 82923, 144789, 177721, 302789, 390123, 642640, 821316, 1390825, 1755400, 2910638, 3833338, 6165743, 8060128, 13322378

Offset

0,7

Links

Table of n, a(n) for n=0..48.

Mathematica

nmax = 48; CoefficientList[Series[Sum[x^(k (k + 1))/Product[(1 - j x^j), {j, 1, k}], {k, 0, nmax}], {x, 0, nmax}], x]

Crossrefs

Cf. A003106, A193196, A204856.

Sequence in context: A163403 A158780 A231208 * A222955 A217208 A287136

Adjacent sequences: A306660 A306661 A306662 * A306664 A306665 A306666

Keyword

nonn

Author

Ilya Gutkovskiy, Mar 04 2019

Status

approved