A055839 T(2n+5,n), where T is the array in A055830.

8, 58, 344, 1918, 10415, 55837, 297374, 1578160, 8359845, 44244825, 234094080, 1238598580, 6555004313, 34703385031, 183805639190, 973982775784, 5163655102685, 27389161216395, 145349642782140, 771718011707550

Offset

0,1

Links

G. C. Greubel, Table of n, a(n) for n = 0..500

Maple

with(combinat);
T:= proc(n, k) option remember;
      if k<0 or k>n then 0
    elif k=0 then fibonacci(n+1)
    elif n=1 and k=1 then 0
    else T(n-1, k-1) + T(n-1, k) + T(n-2, k)
      fi; end:
seq(T(2*n+5, n), n=0..30); # G. C. Greubel, Jan 21 2020

Mathematica

T[n_, k_]:= T[n, k]= If[k<0 || k>n, 0, If[k==0, Fibonacci[n+1], If[n==1 && k==1, 0, T[n-1, k-1] + T[n-1, k] + T[n-2, k]]]]; Table[T[2*n+5, n], {n, 0, 30}] (* G. C. Greubel, Jan 21 2020 *)

Prog

(Sage)
@CachedFunction
def T(n, k):
    if (k<0 and k>n): return 0
    elif (k==0): return fibonacci(n+1)
    elif (n==1 and k==1): return 0
    else: return T(n-1, k-1) + T(n-1, k) + T(n-2, k)
[T(2*n+5, n) for n in (0..30)] # G. C. Greubel, Jan 21 2020

Crossrefs

Cf. A055830.

Sequence in context: A144781 A026948 A111585 * A297097 A081897 A125371

Adjacent sequences: A055836 A055837 A055838 * A055840 A055841 A055842

Keyword

nonn

Author

Clark Kimberling, May 28 2000

Status

approved