%I #9 Nov 08 2017 12:00:05
%S 1,4,64,1778,73848,4188592,306690520,27893327856,3063657097664,
%T 397720778283584,59997757426314624,10373545999796847232,
%U 2032368096229682220160,446879795164524710777856
%N Main diagonal of array in A098697.
%C Diagonal of Euler-Seidel matrix with start sequence A000248.
%F a(n) = Sum_{k=0..n} C(n, k) * A000248(2n-k).
%t a248[0] = 1; a248[n_] := Sum[Binomial[n, k]*(n - k)^k, {k, 0, n}];
%t T[0, n_] := T[0, n] = a248[n]; T[k_, n_] := T[k, n] = T[k - 1, n] + T[k - 1, n + 1];
%t a[n_] := T[n, n];
%t Table[a[n], {n, 0, 13}] (* _Jean-François Alcover_, Nov 08 2017 *)
%K nonn
%O 0,2
%A _Ralf Stephan_, Sep 23 2004