A026702 a(n) = Sum_{k=0..floor(n/2)} T(n-k, k), T given by A026692.

1, 1, 2, 3, 5, 8, 15, 26, 48, 79, 137, 223, 403, 689, 1251, 2088, 3647, 6028, 10775, 18386, 33010, 55460, 96916, 161705, 287199, 490430, 873964, 1475256, 2575673, 4325448, 7646036, 13072664, 23169478, 39254755, 68456542

Offset: 0

Author

Clark Kimberling

Keywords

• nonn

Links

• Vincenzo Librandi, Table of n, a(n) for n = 0..1000

Programs

Mathematica

T[, 0] = 1; T[n, n_] = 1; T[n_, k_] /; EvenQ[k] && 1 <= k/2 <= Floor[n/4] || EvenQ[n - k] && 1 <= (n - k)/2 <= Floor[n/4] := T[n, k] = T[n - 1, k - 1] + T[n - 2, k - 1] + T[n - 1, k]; T[n_, k_] := T[n, k] = T[n - 1, k - 1] + T[n - 1, k];
a[n_] := Sum[T[n - k, k], {k, 0, Floor[n/2]}];
Table[a[n], {n, 0, 34}] (* Jean-François Alcover, Jul 02 2017 *)