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

1, 311, 433380445, 10478887384420274295559, 72383623935281195994580596438773770789899563140885, 39891231890836797259743675264050089835308134898303203181868683359843686746718703346865629969758112672725599

Offset: 1

Author

Benoit Cloitre, Jun 22 2002

Keywords

• easy
• nonn

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).

Programs

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),","))