A078661 - OEIS

%I #6 Jul 09 2025 23:33:22

%S 1,1,2,1,2,2,3,2,3,3,4,5,5,6,7,8,9,11,12,15,16,19,21,26,28,34,36,44,

%T 48,57,63,72,81,93,104,119,133,150,169,191,213,241,268,301,337,376,

%U 420,469,522,581,647,718,799,886,982,1088,1205,1333,1474,1627,1798,1981,2188,2406

%N a(0) = 1; for n>0, a(n) = 1 + coefficient of x^n in expansion of Product_{ n >= 2, n not of the form 2^k-1 } (1+x^n).

%F a(n) = A078660(n) + 1, n > 0. - _Sean A. Irvine_, Jul 09 2025

%Y Cf. A078659, A078660.

%K nonn

%O 0,3

%A _N. J. A. Sloane_, Dec 15 2002