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 A171739 #13 Feb 13 2017 08:36:03
%S A171739 1,3,54,5832,3779136,14693280768,342764853755904,47976111050506371072,
%T A171739 40290721869103654477234176,203018823308689211155302473269248,
%U A171739 6137885950748052085508841340966822477824,1113403476497577147178633950236927694314586243072
%N A171739 a(n) = 2^(n*(n-1)/2)*3^(n*(n+1)/2).
%H A171739 Vincenzo Librandi, <a href="/A171739/b171739.txt">Table of n, a(n) for n = 0..50</a>
%F A171739 a(-n) = A081955(n).
%F A171739 a(n+1)*a(n-1) = 6*a(n)^2.
%F A171739 G.f.: 1 / (1 - 6^1 / 2 * x / (1 - (6^1 - 1) * 6^1 / 2 * x / (1 - 6^2 / 2 * x / (1 - (6^2 - 1) * 6^2 / 2 * x / ... )))). - _Michael Somos_, Jan 03 2013
%e A171739 1 + 3*x + 54*x^2 + 5832*x^3 + 3779136*x^4 + 14693280768*x^5 + 342764853755904*x^6 + ...
%p A171739 A171739:=n->2^(n*(n-1)/2)*3^(n*(n+1)/2): seq(A171739(n), n=0..15); # _Wesley Ivan Hurt_, Feb 12 2017
%t A171739 Table[2^(n*(n-1)/2) * 3^(n*(n+1)/2), {n, 0, 20}] (* _Vincenzo Librandi_, Jan 03 2013 *)
%o A171739 (PARI) {a(n) = 2^(n*(n-1)/2) * 3^(n*(n+1)/2)}
%Y A171739 Cf. A081955.
%K A171739 nonn,easy
%O A171739 0,2
%A A171739 _Michael Somos_, Dec 17 2009