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 A165636 #9 Feb 25 2019 00:30:37 %S A165636 1,1,3,3,45,45,945,945,14175,14175,467775,467775,638512875,638512875, %T A165636 1915538625,1915538625,488462349375,488462349375,194896477400625, %U A165636 194896477400625,32157918771103125,32157918771103125,2218896395206115625,2218896395206115625,3028793579456347828125,3028793579456347828125,9086380738369043484375 %N A165636 a(n) = A091137(n)/2^n. %F A165636 a(n+1) = a(n)* A141459(n+1). %p A165636 A091137 := proc(n) local a, i, p ; a := 1 ; for i from 1 do p := ithprime(i) ; if p > n+1 then break; end if; a := a*p^floor(n/(p-1)) ; end do: a ; end proc: %p A165636 A165636 := proc(n) A091137(n)/2^n ; end proc: # _R. J. Mathar_, Jul 07 2011 %o A165636 (PARI) a(n)=my(p=primes(primepi(n+1)));prod(i=1,#p,p[i]^(n\(p[i]-1)))>>n \\ _Charles R Greathouse IV_, Jul 07 2011 %Y A165636 Cf. A171080, A001897, A036278. %K A165636 nonn %O A165636 0,3 %A A165636 _Paul Curtz_, Sep 23 2009