A071644 a(n) = A005148(2^n-1)/8^(n-1).

1, 311, 433380445, 10478887384420274295559, 72383623935281195994580596438773770789899563140885, 39891231890836797259743675264050089835308134898303203181868683359843686746718703346865629969758112672725599

Offset

1,2

Comments

Appears to always be an integer. General conjecture: the numbers k such that 8^a is the highest power of 2 dividing A005148(k) is the same sequence as numbers k such that k has exactly (a+1) 1's in its binary representation. Hence this sequence gives the smallest integer of the form A005148(k) /8^(n-1).

Links

Table of n, a(n) for n=1..6.

Prog

(PARI) for(s=1, 8, n=2^s-1; print1(polcoeff(prod(k=1, (n+1)\2, 1+x^(2*k-1), 1+x*O(x^n))^(24*n), n)/24/8^(s-1), ", "))

Crossrefs

Sequence in context: A274236 A213814 A305546 * A139638 A308002 A112542

Adjacent sequences: A071641 A071642 A071643 * A071645 A071646 A071647

Keyword

easy,nonn

Author

Benoit Cloitre, Jun 22 2002

Status

approved