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 A181316 #2 Mar 30 2012 18:37:22
%S A181316 1,2,6,122,32242,85808250,2130201408474,487143290951349930,
%T A181316 1021074261736069185881850,19547957495950654924427730234138,
%U A181316 3408841202663503254998708590894515413082
%N A181316 G.f.: A(x) = exp( Sum_{n>=1} 2*((3^n-1)/2)^(n-1)*x^n/n ).
%C A181316 Conjecture: exp( Sum_{n>=1} (q-1)*((q^n-1)/(q-1))^(n-1)*x^n/n ) is an integer series for all integer q>1.
%e A181316 G.f.: A(x) = 1 + 2*x + 6*x^2 + 122*x^3 + 32242*x^4 +...
%e A181316 log(A(x)) = 2*x + 2*4^1*x^2/2 + 2*13^2*x^3/3 + 2*40^3*x^4/4 + 2*121^4*x^5/5 + 2*364^5*x^6/6 +...+ 2*A003462(n)^(n-1)*x^n/n +...
%o A181316 (PARI) {a(n)=polcoeff(exp(sum(m=1,n,2*((3^m-1)/2)^(m-1)*x^m/m)+x*O(x^n)),n)}
%Y A181316 Cf. A180606.
%K A181316 nonn
%O A181316 0,2
%A A181316 _Paul D. Hanna_, Oct 31 2010