A119969 Sum{k>=0, C(2^k-1,n-2*(2^k-1))}.

1, 0, 1, 1, 0, 0, 1, 3, 3, 1, 0, 0, 0, 0, 1, 7, 21, 35, 35, 21, 7, 1, 0, 0, 0, 0, 0, 0, 0, 0, 1, 15, 105, 455, 1365, 3003, 5005, 6435, 6435, 5005, 3003, 1365, 455, 105, 15, 1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1, 31, 465, 4495, 31465, 169911, 736281, 2629575

Offset

0,8

Links

Table of n, a(n) for n=0..69.

Formula

G.f.: sum{k>=0, (x^2*(1+x))^(2k-1)}; a(n)=sum{k=0..floor(n/2), C(k,n-2k)*mod(C(k),2)}; a(n)=sum{k=0..floor(n/2), C(k,n-2k)*A036987(k)}.

Crossrefs

Sequence in context: A096964 A350483 A123254 * A051343 A356326 A261477

Adjacent sequences: A119966 A119967 A119968 * A119970 A119971 A119972

Keyword

easy,nonn

Author

Paul Barry, Jun 01 2006

Status

approved