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 A047796 #29 Jan 18 2025 16:35:45
%S A047796 1,1,2,14,194,4402,147552,6838764,418389078,32639603798,3161107700156,
%T A047796 372023906062756,52280302234036252,8645773770675973804,
%U A047796 1661888635268695003484,367390786215560629372920,92552610850186107484661670,26356304249588730696338349990
%N A047796 a(n) = Sum_{k=0..n} Stirling1(n,k)^2.
%H A047796 Vincenzo Librandi and Vaclav Kotesovec, <a href="/A047796/b047796.txt">Table of n, a(n) for n = 0..250</a> (terms 0..41 from Vincenzo Librandi)
%p A047796 seq(add(stirling1(n, k)^2, k = 0..n), n = 0..20); # _G. C. Greubel_, Aug 07 2019
%t A047796 Table[Sum[StirlingS1[n,k]^2,{k,0,n}],{n,0,20}] (* _Emanuele Munarini_, Jul 04 2011 *)
%o A047796 (Maxima) makelist(sum(stirling1(n,k)^2,k,0,n),n,0,24); /* _Emanuele Munarini_, Jul 04 2011 */
%o A047796 (PARI) a(n) = sum(k=0, n, stirling(n, k, 1)^2); \\ _Michel Marcus_, Mar 26 2016
%o A047796 (Magma) [(&+[StirlingFirst(n,k)^2: k in [0..n]]): n in [0..10]]; // _G. C. Greubel_, Aug 07 2019
%o A047796 (Sage) [sum(stirling_number1(n,k)^2 for k in (0..n)) for n in (0..20)] # _G. C. Greubel_, Aug 07 2019
%o A047796 (GAP) List([0..20], n-> Sum([0..n], k-> Stirling1(n,k)^2 )); # _G. C. Greubel_, Aug 07 2019
%Y A047796 Cf. A000275, A047797, A342111.
%K A047796 nonn
%O A047796 0,3
%A A047796 _N. J. A. Sloane_