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 A371686 #11 Apr 07 2024 03:50:37 %S A371686 1,1,2,1,4,5,1,6,15,16,1,8,30,64,65,1,10,50,160,325,326,1,12,75,320, %T A371686 975,1956,1957,1,14,105,560,2275,6846,13699,13700,1,16,140,896,4550, %U A371686 18256,54796,109600,109601,1,18,180,1344,8190,41076,164388,493200,986409,986410 %N A371686 Triangle read by rows: T(n, k) = e * binomial(n, k) * Gamma(k + 1, 1). %F A371686 T(n, k) = (n! / (n - k)!)*(Sum_{j = 0..k} (1 / j!)). - _Detlef Meya_, Apr 06 2024 %e A371686 Triangle starts: %e A371686 [0] 1; %e A371686 [1] 1, 2; %e A371686 [2] 1, 4, 5; %e A371686 [3] 1, 6, 15, 16; %e A371686 [4] 1, 8, 30, 64, 65; %e A371686 [5] 1, 10, 50, 160, 325, 326; %e A371686 [6] 1, 12, 75, 320, 975, 1956, 1957; %e A371686 [7] 1, 14, 105, 560, 2275, 6846, 13699, 13700; %p A371686 T := (n, k) -> binomial(n, k)*GAMMA(k + 1, 1)*exp(1): %p A371686 seq(seq(simplify(T(n, k)), k = 0..n), n = 0..9); %t A371686 T[n_,k_]:=(n!/(n-k)!)*Sum[1/j!,{j,0,k}];Flatten[Table[T[n,k],{n,0,9},{k,0,n}]] (* _Detlef Meya_, Apr 06 2024 *) %Y A371686 Cf. A000522 (main diagonal), A007526 (subdiagonal), A010842 (row sums), A000142 and A133942 (alternating row sums), A367963 (central terms). %K A371686 nonn,tabl %O A371686 0,3 %A A371686 _Peter Luschny_, Apr 03 2024