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 A130470 #3 Sep 08 2022 08:45:30 %S A130470 1,1,3,8,29,135,775,5302,41841,373349,3711707,40658196,486383173, %T A130470 6307963843,88147345839,1320249637490,21098598196505,358321619407137, %U A130470 6444482754775171,122360423398008784,2445769875087993837 %N A130470 Antidiagonal sums of triangular array T: T(j,k) = k*(j-k)! for k < j, T(j,k) = 1 for k = j; 1 <= k <= j. %e A130470 Antidiagonal starting at T(7,1) is 720, 48, 6, 1, so a(7) = 775. %o A130470 (Magma) m:=21; T:=[ [ k*Factorial(j-k): k in [1..j-1] ] cat [ 1 ]: j in [1..m] ]; [ &+[ T[j-k+1][k]: k in [1..(j+1) div 2] ]: j in [1..m] ]; %Y A130470 Cf. A130469 (T read by rows), A129867 (row sums of T), A130471 (first differences). %K A130470 nonn %O A130470 1,3 %A A130470 _Klaus Brockhaus_, May 28 2007