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 A228193 #6 Aug 20 2024 15:31:56
%S A228193 1,3,165,488007,63015285321,313849204040245803,
%T A228193 57549960579131376060801997,379048169979935686476204047966170767,
%U A228193 88353684521579654155696728418892273040483607185,721871639878336367921338532273490438662977816273231098545619
%N A228193 G.f.: exp( Sum_{n>=1} A001850(n^2)*x^n/n ), where A001850 forms the central Delannoy numbers.
%F A228193 Logarithmic derivative yields A228192.
%e A228193 G.f.: A(x) = 1 + 3*x + 165*x^2 + 488007*x^3 + 63015285321*x^4 +...
%e A228193 where the logarithm of the g.f. begins:
%e A228193 log(A(x)) = 3*x + 321*x^2/2 + 1462563*x^3/3 + 252055236609*x^4/4 +...+ A001850(n^2)*x^n/n +...
%o A228193 (PARI) {A228192(n)=sum(k=0,n^2,binomial(n^2,k)*binomial(n^2+k,k))}
%o A228193 {a(n)=polcoeff(exp(sum(k=1,n+1,A228192(k)*x^k/k) +x*O(x^n)),n)}
%o A228193 for(n=0,20,print1(a(n),", "))
%Y A228193 Cf. A228192, A001850.
%K A228193 nonn
%O A228193 0,2
%A A228193 _Paul D. Hanna_, Aug 15 2013