A107948 Terms at positions 2^n of A107946 for n>=0.

1, 1, 2, 5, 16, 68, 399, 3348, 41417, 775234, 22445788, 1024347395, 74876701760, 8888457145166, 1734062627778860

Offset: 0

Author

Paul D. Hanna, May 28 2005

Keywords

• nonn

Crossrefs

Cf. A107946, A107947.

Programs

PARI

{a(n)=local(A=[1,1],B=[1]);for(i=1,n-1, B=concat(B,vector(#B,k,polcoeff(Ser(A)/(1-x),#B+k-1))); A=concat(A,B););A[2^(n-1)]}

Formula

a(n) = A107946(2^n).