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

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

Offset

0,2

Comments

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

Links

Table of n, a(n) for n=0..12.

Formula

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

Prog

(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])}

Crossrefs

Cf. A107946, A107947, A107948, A107957.

Sequence in context: A129833 A321585 A368283 * A378159 A253972 A053557

Adjacent sequences: A107955 A107956 A107957 * A107959 A107960 A107961

Keyword

nonn

Author

Paul D. Hanna, May 29 2005

Status

approved