A107958 a(n) = term at position 2^n in A107957.

1, 3, 11, 52, 331, 2949, 38069, 733817, 21670554, 1001901607, 73852354365, 8813580443406, 1725174170633694

Offset: 0

Author

Paul D. Hanna, May 29 2005

Keywords

• nonn

Comments

Also terms at positions 2^(n+1) - 1 of A107947, where A107947 equals the first differences of A107957.

Crossrefs

Cf. A107946, A107947, A107948, A107957.

Programs

PARI

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

Formula

a(n) = A107957(2^n). a(n) = A107947(2^(n+1) - 1).