OFFSET
0,2
COMMENTS
Aerated sequence gives diagonal sums of A166353.
FORMULA
a(n)=sum{k=0..n, C(n+k,2k)*G(k)} where G(n)=0^n+2(-1)^n*(1-4^n)*sum{k=0..2n, sum{j=0..k, (-1)^j*C(k,j)*j^(2n)/(k+1)}}.
MATHEMATICA
(* The function RiordanArray is defined in A256893. *)
nmax = 17; R = RiordanArray[1 + # Tan[#/2]&, #&, 2 nmax + 1, True];
a[n_] := Sum[R[[i, 2 n - i + 2]], {i, 2 n + 1, n + 1, -1}];
Table[a[n], {n, 0, nmax}] (* Jean-François Alcover, Jul 20 2019 *)
CROSSREFS
KEYWORD
easy,nonn
AUTHOR
Paul Barry, Oct 12 2009
STATUS
approved