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 A335977 #30 Jul 07 2020 08:56:18 %S A335977 1,1,1,1,0,1,1,-1,-1,1,1,-2,-1,-1,1,1,-3,1,3,2,1,1,-4,5,7,7,9,1,1,-5, %T A335977 11,5,-8,-13,9,1,1,-6,19,-9,-43,-65,-89,-50,1,1,-7,29,-41,-74,-27,37, %U A335977 -45,-267,1,1,-8,41,-97,-53,221,597,1024,1191,-413,1,1,-9,55,-183,92,679,961,805,1351,4723,2180,1 %N A335977 Square array T(n,k), n>=0, k>=0, read by antidiagonals downwards, where column k is the expansion of e.g.f. exp(k*(1 - exp(x)) + x). %H A335977 Seiichi Manyama, <a href="/A335977/b335977.txt">Antidiagonals n = 0..139, flattened</a> %F A335977 T(0,k) = 1 and T(n,k) = T(n-1,k) - k * Sum_{j=0..n-1} binomial(n-1,j) * T(j,k) for n > 0. %F A335977 T(n,k) = exp(k) * Sum_{j>=0} (j + 1)^n * (-k)^j / j!. %e A335977 Square array begins: %e A335977 1, 1, 1, 1, 1, 1, 1, ... %e A335977 1, 0, -1, -2, -3, -4, -5, ... %e A335977 1, -1, -1, 1, 5, 11, 19, ... %e A335977 1, -1, 3, 7, 5, -9, -41, ... %e A335977 1, 2, 7, -8, -43, -74, -53, ... %e A335977 1, 9, -13, -65, -27, 221, 679, ... %e A335977 1, 9, -89, 37, 597, 961, -341, ... %t A335977 T[0, k_] := 1; T[n_, k_] := T[n - 1, k] - k * Sum[T[j, k] * Binomial[n - 1, j], {j, 0, n - 1}]; Table[T[n - k, k], {n, 0, 11}, {k, n, 0, -1}] // Flatten (* _Amiram Eldar_, Jul 03 2020 *) %Y A335977 Columns k=0-4 give: A000012, A293037, A309775, A320432, A320433. %Y A335977 Main diagonal gives A334241. %Y A335977 Cf. A292861, A335975. %K A335977 sign,tabl,look %O A335977 0,12 %A A335977 _Seiichi Manyama_, Jul 03 2020