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 A239682 #6 Mar 24 2014 04:28:24 %S A239682 1,1,2,2,8,16,96,96,192,768,7680,15360,184320,1105920,8847360,8847360, %T A239682 141557760,283115520,5096079360,20384317440,244611809280, %U A239682 2446118092800,53814598041600,107629196083200,430516784332800,5166201411993600,10332402823987200 %N A239682 Product_{i=1..n} A173557(i). %C A239682 This is the generalized factorial for A173557. %H A239682 Donald E. Knuth and Herbert S. Wilf, <a href="http://www.math.upenn.edu/~wilf/website/dm36.pdf">The power of a prime that divides a generalized binomial coefficient</a>, J. Reine Angew. Math., 396:212-219, 1989. %F A239682 Product_{i=1..n} A173557(i). %F A239682 a(n) = abs(A085542(n)). %e A239682 The first five terms of A173557 are 1,1,2,1,4 so a(5)=4*1*2*1*1=8. %o A239682 (Sage) %o A239682 q=50 # change q for more terms %o A239682 R=[prod([(x-1) for x in prime_divisors(n)]) for n in [1..q]] %o A239682 [prod(R[0:i+1]) for i in [0..q-1]] %Y A239682 Cf. A173557, A085542, A048803. %K A239682 nonn %O A239682 1,3 %A A239682 _Tom Edgar_, Mar 24 2014