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 A258311 #8 May 01 2022 12:33:22 %S A258311 1,1,3,7,26,86,392,1660,9065,46705,297984,1805926,13186497,91788477, %T A258311 754481662,5924676900,54092804430,472512732558,4739696836485, %U A258311 45540919862179,497377234156959,5208759709993591,61475622078245542,696384168181553136,8825761698420052542 %N A258311 Row sums of A258310. %H A258311 Alois P. Heinz, <a href="/A258311/b258311.txt">Table of n, a(n) for n = 0..500</a> %F A258311 a(n) = Sum_{k=0..floor(n/2)} A258310(n,k). %p A258311 b:= proc(x, y, t, k) option remember; `if`(y>x or y<0, 0, %p A258311 `if`(x=0, 1, b(x-1, y-1, false, k)*`if`(t, (k*x+y)/y, 1) %p A258311 +b(x-1, y, false, k) +b(x-1, y+1, true, k))) %p A258311 end: %p A258311 A:= (n, k)-> b(n, 0, false, k): %p A258311 T:= proc(n, k) option remember; %p A258311 add(A(n, i)*(-1)^(k-i)*binomial(k, i), i=0..k)/k! %p A258311 end: %p A258311 a:= proc(n) option remember; add(T(n, k), k=0..n/2) end: %p A258311 seq(a(n), n=0..30); %t A258311 b[x_, y_, t_, k_] := b[x, y, t, k] = If[y > x || y < 0, 0, %t A258311 If[x == 0, 1, b[x - 1, y - 1, False, k]*If[t, (k*x + y)/y, 1] %t A258311 + b[x - 1, y, False, k] + b[x - 1, y + 1, True, k]]]; %t A258311 A[n_, k_] := b[n, 0, False, k]; %t A258311 T[n_, k_] := Sum[A[n, i] (-1)^(k - i) Binomial[k, i], {i, 0, k}]/k!; %t A258311 a[n_] := Sum[T[n, k], {k, 0, n/2}]; %t A258311 Table[a[n], {n, 0, 30}] (* _Jean-François Alcover_, May 01 2022, after _Alois P. Heinz_ *) %Y A258311 Cf. A258310. %K A258311 nonn %O A258311 0,3 %A A258311 _Alois P. Heinz_, May 25 2015