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A026788 a(n) = Sum_{k=0..floor(n/2)} T(n,k), T given by A026780. 11
1, 1, 4, 6, 20, 34, 105, 191, 563, 1071, 3057, 6007, 16745, 33729, 92332, 189662, 511812, 1068178, 2849404, 6025594, 15921514, 34043204, 89242582, 192621212, 501574732, 1091400122, 2825710822, 6192005260, 15952433940, 35172854946 (list; graph; refs; listen; history; text; internal format)
OFFSET
0,3
LINKS
MAPLE
T:= proc(n, k) option remember;
if n<0 then 0;
elif k=0 or k =n then 1;
elif k <= n/2 then
procname(n-1, k-1)+procname(n-2, k-1)+procname(n-1, k) ;
else
procname(n-1, k-1)+procname(n-1, k) ;
fi ;
end proc:
seq( add(T(n, k), k=0..floor(n/2)), n=0..30); # G. C. Greubel, Nov 02 2019
MATHEMATICA
T[n_, k_]:= T[n, k]= If[n<0, 0, If[k==0 || k==n, 1, If[k<=n/2, T[n-1, k-1] + T[n-2, k-1] + T[n-1, k], T[n-1, k-1] + T[n-1, k] ]]];
Table[Sum[T[n, k], {k, 0, Floor[n/2]}], {n, 0, 30}] (* G. C. Greubel, Nov 02 2019 *)
PROG
(Sage)
@CachedFunction
def T(n, k):
if (n<0): return 0
elif (k==0 or k==n): return 1
elif (k<=n/2): return T(n-1, k-1) + T(n-2, k-1) + T(n-1, k)
else: return T(n-1, k-1) + T(n-1, k)
[sum(T(n, k) for k in (0..floor(n/2))) for n in (0..30)] # G. C. Greubel, Nov 02 2019
CROSSREFS
Sequence in context: A066193 A026711 A273995 * A079435 A227959 A088015
KEYWORD
nonn
AUTHOR
STATUS
approved

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Last modified March 28 04:05 EDT 2024. Contains 371235 sequences. (Running on oeis4.)