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 A371997 #7 Apr 24 2024 12:46:02 %S A371997 1,1,1,1,17,17,1,98,1585,1585,1,354,30259,485729,485729,1,979,280883, %T A371997 23237252,372281761,372281761,1,2275,1702758,459143300,37562889061, %U A371997 601378506737,601378506737,1,4676,7762854,5310927050,1397160213861,113771355829478,1820943071778385,1820943071778385 %N A371997 Triangle read by rows: T(m, n, k) = 1 if k = 0 and T(m, n, k - 1) if k = n; otherwise (-1)^m*(k - n - 1)^m * T(m, n, k - 1) + T(m, n - 1, k) where m = 4. %e A371997 Triangle begins: %e A371997 [0] 1; %e A371997 [1] 1, 1; %e A371997 [2] 1, 17, 17; %e A371997 [3] 1, 98, 1585, 1585; %e A371997 [4] 1, 354, 30259, 485729, 485729; %e A371997 [5] 1, 979, 280883, 23237252, 372281761, 372281761; %e A371997 [6] 1, 2275, 1702758, 459143300, 37562889061, 601378506737, 601378506737; %p A371997 T := proc(m, n, k) option remember; if k = 0 then 1 elif k = n then T(m, n, k-1) else (-1)^m*(k - n - 1)^m * T(m, n, k - 1) + T(m, n - 1, k) fi end: %p A371997 seq(seq(T(4, n, k), k = 0..n), n = 0..8)); %Y A371997 Family: A009766 (Catalan's triangle, m=0), A001498 (m=1), A060058 (m=2), A371996 (m=3), this triangle (m=4). %Y A371997 Cf. A227887 (main diagonal). %K A371997 nonn,tabl %O A371997 0,5 %A A371997 _Peter Luschny_, Apr 24 2024