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A026775 a(n) = T(n, floor(n/2)), T given by A026769. 11
1, 1, 2, 4, 7, 17, 28, 76, 120, 352, 538, 1674, 2493, 8129, 11854, 40156, 57558, 201236, 284392, 1020922, 1426038, 5234660, 7241356, 27089726, 37173304, 141335846, 192638992, 742712598, 1006564439, 3927908193, 5297715628 (list; graph; refs; listen; history; text; internal format)
OFFSET

0,3

LINKS

G. C. Greubel, Table of n, a(n) for n = 0..1000

MAPLE

T:= proc(n, k) option remember;

   if n<0 then 0;

   elif k=0 or k=n then 1;

   elif n=2 and k=1 then 2;

   elif k <= (n-1)/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) ;

   end if ;

end proc;

seq(T(n, floor(n/2)), n=0..30); # G. C. Greubel, Nov 01 2019

MATHEMATICA

T[n_, k_]:= T[n, k]= If[n<0, 0, If[k==0 || k==n, 1, If[n==2 && k==1, 2, If[k<=(n-1)/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[T[n, Floor[n/2]], {n, 0, 30}] (* G. C. Greubel, Nov 01 2019 *)

PROG

(Sage)

@CachedFunction

def T(n, k):

    if (k==0 or k==n): return 1

    elif (n==2 and k==1): return 2

    elif (k<=(n-1)/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)

[T(n, floor(n/2)) for n in (0..30)] # G. C. Greubel, Nov 01 2019

CROSSREFS

Cf. A026769, A026770, A026771, A026772, A026773, A026774, A026776, A026777, A026778, A026779.

Sequence in context: A113878 A293793 A301745 * A299294 A299102 A027238

Adjacent sequences:  A026772 A026773 A026774 * A026776 A026777 A026778

KEYWORD

nonn,changed

AUTHOR

Clark Kimberling

STATUS

approved

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Last modified November 13 07:13 EST 2019. Contains 329085 sequences. (Running on oeis4.)