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 A144658 #14 Aug 14 2019 14:15:49
%S A144658 0,6,222,5052,109512,2432448,55611294,1301187912,30992726652,
%T A144658 748573575780,18283412752602,450657126652626,11192820097106112,
%U A144658 279787295335659972,7032532241701837758,177611430241032329568
%N A144658 a(n) = Sum_{i=1..n} Sum_{j=1..n} Sum_{k=1..n} (i+j+k)!/(i!*j!*k!).
%H A144658 Seiichi Manyama, <a href="/A144658/b144658.txt">Table of n, a(n) for n = 0..100</a>
%t A144658 Table[Sum[Sum[Sum[(i+j+k)!/i!/j!/k!,{i,1,n}],{j,1,n}],{k,1,n}],{n,1,30}]
%o A144658 (PARI) {a(n) = sum(i=1, n, sum(j=1, n, sum(k=1, n, (i+j+k)!/(i!*j!*k!))))} \\ _Seiichi Manyama_, May 19 2019
%o A144658 (PARI) {a(n) = sum(i=3, 3*n, i!*polcoef(sum(j=1, n, x^j/j!)^3, i))} \\ _Seiichi Manyama_, May 19 2019
%Y A144658 Cf. A144511.
%K A144658 nonn
%O A144658 0,2
%A A144658 _N. J. A. Sloane_, Jan 30 2009