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 A348014 #22 Sep 25 2021 06:42:29 %S A348014 1,1,1,1,5,4,1,32,139,108,1,288,8331,35692,27648,1,3413,908331, %T A348014 26070067,111565148,86400000,1,50069,160145259,42405161203, %U A348014 1216436611100,5205269945088,4031078400000 %N A348014 Triangle, read by rows, with row n forming the coefficients in Product_{k=0..n} (1 + k^k*x). %H A348014 Seiichi Manyama, <a href="/A348014/b348014.txt">Rows n = 0..37, flattened</a> %F A348014 T(0,0) = 1; T(n,k) = T(n-1,k) + n^n * T(n-1,k-1). %e A348014 Triangle begins: %e A348014 1; %e A348014 1, 1; %e A348014 1, 5, 4; %e A348014 1, 32, 139, 108; %e A348014 1, 288, 8331, 35692, 27648; %e A348014 1, 3413, 908331, 26070067, 111565148, 86400000; %o A348014 (PARI) T(n, k) = if(k==0, 1, if(k==n, prod(j=1, n, j^j), T(n-1, k)+n^n*T(n-1, k-1))); %o A348014 (PARI) row(n) = Vecrev(prod(k=1, n, 1+k^k*x)); %Y A348014 Column k=1 gives A001923. %Y A348014 The diagonal of the triangle is A002109. %Y A348014 Cf. A007318, A008955, A023531, A108084, A173007, A173008, A249677. %K A348014 nonn,tabl %O A348014 0,5 %A A348014 _Seiichi Manyama_, Sep 24 2021