A373188 - OEIS

%I #12 May 27 2024 09:56:11

%S 1,2,3,5,5,6,7,10,9,10,11,15,13,14,15,21,17,18,19,25,21,22,23,30,25,

%T 26,27,35,29,30,31,42,33,34,35,45,37,38,39,50,41,42,43,55,45,46,47,63,

%U 49,50,51,65,53,54,55,70,57,58,59,75,61,62,63,85,65,66,67,85,69,70,71,90,73,74,75,95,77,78,79,105,81,82,83,105,85,86

%N Expansion of Sum_{k>=0} x^(4^k) / (1 - x^(4^k))^2.

%F G.f. A(x) satisfies A(x) = x/(1 - x)^2 + A(x^4).

%F a(4*n+1) = 4*n+1, a(4*n+2) = 4*n+2, a(4*n+3) = 4*n+3 and a(4*n+4) = 4*n+4 + a(n+1) for n >= 0.

%Y Cf. A373187, A373189.

%Y Cf. A129527, A327625, A359100.

%K nonn

%O 1,2

%A _Seiichi Manyama_, May 27 2024