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 A047798 #12 Sep 08 2022 08:44:57
%S A047798 1,1,3,31,443,9006,241147,7956579,318973867,15061651528,824029357046,
%T A047798 51526959899570,3636995712432667,287053182699020609,
%U A047798 25126145438688593769,2421761360666327615911,255466264644678162575691,29336098320197429601856772
%N A047798 a(n) = Sum_{k=0..n} C(n,k)*Stirling2(n,k)^2.
%H A047798 G. C. Greubel, <a href="/A047798/b047798.txt">Table of n, a(n) for n = 0..300</a>
%p A047798 seq(add(binomial(n,k)*stirling2(n, k)^2, k = 0..n), n = 0..20); # _G. C. Greubel_, Aug 07 2019
%t A047798 Table[Sum[Binomial[n, k]*StirlingS2[n, k]^2, {k,0,n}], {n,0,20}] (* _G. C. Greubel_, Aug 07 2019 *)
%o A047798 (PARI) {a(n) = sum(k=0,n, binomial(n,k)*stirling(n,k,2)^2)};
%o A047798 vector(20, n, n--; a(n)) \\ _G. C. Greubel_, Aug 07 2019
%o A047798 (Magma) [(&+[Binomial(n,k)*StirlingSecond(n,k)^2: k in [0..n]]): n in [0..20]]; // _G. C. Greubel_, Aug 07 2019
%o A047798 (Sage) [sum(binomial(n,k)*stirling_number2(n,k)^2 for k in (0..n)) for n in (0..20)] # _G. C. Greubel_, Aug 07 2019
%o A047798 (GAP) List([0..20], n-> Sum([0..n], k-> Binomial(n,k)*Stirling2(n,k)^2 )); # _G. C. Greubel_, Aug 07 2019
%Y A047798 Cf. A008277, A047799, A211210, A317274.
%K A047798 nonn
%O A047798 0,3
%A A047798 _N. J. A. Sloane_