A101562 a(n)=(-1)^n*coefficient of x^n in sum{k>=1,x^(k-1)/(1+4x^k)}.

1, 3, 17, 67, 257, 1011, 4097, 16451, 65553, 261891, 1048577, 4195379, 16777217, 67104771, 268435729, 1073758275, 4294967297, 17179804659, 68719476737, 274878168899, 1099511631889, 4398045462531, 17592186044417, 70368748389427

Offset

0,2

Links

Table of n, a(n) for n=0..23.

Formula

a(n)=sum{k=0..n, (-1)^(n-k)*if(mod(n+1, k+1)=0, 1, 0)*4^k}

Crossrefs

Cf. A051731, A081295, A048272, A101561, A101563.

Sequence in context: A227427 A120386 A061982 * A034566 A357923 A069468

Adjacent sequences: A101559 A101560 A101561 * A101563 A101564 A101565

Keyword

easy,nonn

Author

Paul Barry, Dec 07 2004

Status

approved