This is a front-end for the Online Encyclopedia of Integer Sequences, made by Christian Perfect. The idea is to provide OEIS entries in non-ancient HTML, and then to think about how they're presented visually. The source code is on GitHub.
%I A071644 #9 Jan 31 2022 19:37:49 %S A071644 1,311,433380445,10478887384420274295559, %T A071644 72383623935281195994580596438773770789899563140885, %U A071644 39891231890836797259743675264050089835308134898303203181868683359843686746718703346865629969758112672725599 %N A071644 a(n) = A005148(2^n-1)/8^(n-1). %C A071644 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). %o A071644 (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),",")) %K A071644 easy,nonn %O A071644 1,2 %A A071644 _Benoit Cloitre_, Jun 22 2002