A274716 - OEIS

%I #5 Jul 07 2016 18:10:53

%S 0,0,1,0,3,1,4,0,7,3,8,1,10,4,11,0,15,7,16,3,18,8,19,1,22,10,23,4,25,

%T 11,26,0,31,15,32,7,34,16,35,3,38,18,39,8,41,19,42,1,46,22,47,10,49,

%U 23,50,4,53,25,54,11,56,26,57,0,63,31,64,15,66,32,67,7,70,34,71,16,73,35,74,3,78,38,79,18,81,39,82,8,85,41,86,19,88,42,89,1,94,46,95,22,97,47,98,10,101,49,102,23,104,50,105,4,109,53,110,25,112,54,113,11,116,56,117,26,119,57,120,0

%N a(2*n+1) = a(2*floor(n/2)+1) + n, a(2*n) = a(n), for n>=1 with a(1)=0.

%C The values {2^a(n)} form the denominators of the coefficients in the g.f. of A274717, which satisfies G(x) = G(x^2) + sqrt( G(x^2) ).

%F a(2^n) = 0 for n>=0.

%F a(2*n-1) = A005187(n-1) for n>=1.

%o (PARI) {a(n) = if(n==1,0, if(n%2==0, a(n/2), a(2*(n\4)+1) + n\2 ) )}

%o for(n=1,32,print1(a(n),", "))

%Y Cf. A274717, A005187.

%K nonn

%O 1,5

%A _Paul D. Hanna_, Jul 07 2016