A308806 - OEIS

%I #6 Jun 25 2019 18:48:56

%S 1,1,1,1,1,2,3,4,5,6,8,11,14,18,23,30,40,52,67,86,111,145,188,243,314,

%T 406,527,683,883,1141,1475,1910,2474,3201,4140,5355,6929,8968,11603,

%U 15009,19416,25121,32507,42060,54413,70393,91071,117831,152453,197238,255175,330137,427130,552620

%N Expansion of 1 / Sum_{k>=0} (-x)^(k*(3*k - 1)/2).

%F G.f.: 1 / Sum_{k>=0} (-x)^A000326(k).

%t nmax = 53; CoefficientList[Series[1/Sum[(-x)^(k (3 k - 1)/2), {k, 0, nmax}], {x, 0, nmax}], x]

%Y Cf. A000041, A000326, A006950, A181324, A208061, A317665.

%K nonn

%O 0,6

%A _Ilya Gutkovskiy_, Jun 25 2019