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 A128226 #12 Feb 18 2022 22:09:03
%S A128226 1,4,2,7,7,3,10,12,10,4,13,17,17,13,5,16,22,24,22,16,6,19,27,31,31,27,
%T A128226 19,7,22,32,38,40,38,32,22,8,25,37,45,49,49,45,37,25,9,28,42,52,58,60,
%U A128226 58,52,42,28,10
%N A128226 Triangle, A004736 * A127899 (unsigned).
%C A128226 Row sums = A084990: (1, 6, 17, 36, 65, 106, ...).
%C A128226 A128225 = A127899(unsigned) * A004736.
%F A128226 A004736 * A127899 (unsigned). By columns, (3k+1), (5k+2), (7k+3), ...; k=0,1,2...
%e A128226 First few row of the triangle are:
%e A128226 1;
%e A128226 4, 2;
%e A128226 7, 7, 3;
%e A128226 10, 12, 10, 4;
%e A128226 13, 17, 17, 13, 5;
%e A128226 16, 22, 24, 22, 16, 6;
%e A128226 19, 27, 31, 31, 27, 19, 7;
%e A128226 ...
%t A128226 (* a127899U computes the unsigned version of A127899 *)
%t A128226 a127899U[n_, k_] := If[n==k||n-1==k, n, 0]/;(1<=k<=n)
%t A128226 a004736[n_, k_] := n-k+1/;(1<=k<=n+1)
%t A128226 a128225[n_, k_] := a127899U[n, n](a004736[n, k] + a004736[n-1, k])/;(1<=k<=n)
%t A128226 a128225[r_] := Table[a128225[n, k], {n, 1, r}, {k, 1, n}]
%t A128226 TableForm[a128225[7]] (* triangle *)
%t A128226 Flatten[a128225[10]] (* data *) (* _Hartmut F. W. Hoft_, Mar 13 2017 *)
%Y A128226 Cf. A004736, A084990, A127899, A128225.
%K A128226 nonn,tabl
%O A128226 1,2
%A A128226 _Gary W. Adamson_, Feb 19 2007