login
A107957
Partial sums of A107947.
1
1, 3, 6, 11, 17, 25, 36, 52, 69, 88, 110, 137, 170, 211, 263, 331, 400, 471, 545, 624, 709, 802, 906, 1026, 1163, 1319, 1497, 1702, 1940, 2219, 2550, 2949, 3349, 3751, 4156, 4566, 4982, 5406, 5841, 6292, 6760, 7247, 7756, 8292, 8861, 9471, 10133, 10863
OFFSET
0,2
COMMENTS
Terms at positions 2^k is found in A107958.
FORMULA
a(n) = A107947(2^m + n) - A107947(2^m) when n <= 2^(m-1).
EXAMPLE
a(3) = 6 = 22 - 16 = A107947(2^3 + 3) - A107947(2^3).
a(5) = 17 = 85 - 68 = A107947(2^4 + 5) - A107947(2^4).
a(8) = 52 = 120 - 68 = A107947(2^4 + 8) - A107947(2^4).
PROG
(PARI) {a(n)=local(A=[1, 2]); for(i=1, #binary(n), B=vector(#A, k, polcoeff(Ser(A)/(1-x), k-1)+A[2^#binary(#A-1)]); A=concat(A, B); ); sum(k=1, n, A[k])}
CROSSREFS
KEYWORD
nonn
AUTHOR
Paul D. Hanna, May 29 2005
STATUS
approved