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 A062197 #28 Sep 08 2022 08:45:03
%S A062197 1,2,5,14,37,34,-887,-14050,-168919,-1916542,-21607859,-245387858,
%T A062197 -2799384755,-31558843486,-337767590383,-3063846770626,
%U A062197 -11912361112367,477367592119810,21032925955607701,627398853149961038,16703816669710968821
%N A062197 Row sums of signed triangle A062139 (generalized a=2 Laguerre).
%H A062197 G. C. Greubel, <a href="/A062197/b062197.txt">Table of n, a(n) for n = 0..448</a>
%H A062197 <a href="/index/La#Laguerre">Index entries for sequences related to Laguerre polynomials</a>
%F A062197 E.g.f.: exp(-x/(1-x))/(1-x)^3.
%F A062197 a(n) = Sum_{m=0..n} ((-1)^m)*n!*binomial(n+2, n-m)/m!.
%F A062197 a(n) = 2*n*a(n-1) - (n-1)*(n+1)*a(n-2). - _Vaclav Kotesovec_, Aug 01 2013
%F A062197 a(n) = (n+2)!*hypergeom([-n],[3],1)/2. - _Peter Luschny_, Apr 11 2015
%p A062197 a := n -> (n+2)!*hypergeom([-n],[3],1)/2:
%p A062197 seq(simplify(a(n)), n=0..20); # _Peter Luschny_, Apr 11 2015
%t A062197 Table[n!*LaguerreL[n, 2, 1],{n,0,20}] (* _Vaclav Kotesovec_, Aug 01 2013 *)
%o A062197 (PARI) for(n=0,30, print1(n!*sum(k=0,n, (-1)^k*binomial(n+2, n-k)/k!), ", ")) \\ _G. C. Greubel_, May 13 2018
%o A062197 (PARI) a(n) = vecsum(Vec(n!*pollaguerre(n, 2))); \\ _Michel Marcus_, Feb 06 2021
%o A062197 (Magma) [Factorial(n)*(&+[(-1)^k*Binomial(n+2, n-k)/Factorial(k): k in [0..n]]): n in [0..30]]; // _G. C. Greubel_, May 13 2018
%Y A062197 Cf. A062139.
%K A062197 sign,easy
%O A062197 0,2
%A A062197 _Wolfdieter Lang_, Jun 19 2001