The OEIS is supported by the many generous donors to the OEIS Foundation.

 Hints (Greetings from The On-Line Encyclopedia of Integer Sequences!)
 A026777 a(n) = Sum_{k=0..floor(n/2)} T(n,k), T given by A026769. 11
 1, 1, 3, 5, 14, 26, 70, 138, 362, 742, 1912, 4028, 10249, 22033, 55547, 121273, 303641, 670997, 1671233, 3729071, 9250099, 20803231, 51437219, 116436313, 287152067, 653567143, 1608416195, 3677760541, 9035150126, 20741496354 (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( add(T(n, k), k=0..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[Sum[T[n, k], {k, 0, 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) [sum(T(n, k) for k in (0..floor(n/2))) for n in (0..30)] # G. C. Greubel, Nov 01 2019 CROSSREFS Cf. A026769, A026770, A026771, A026772, A026773, A026774, A026775, A026776, A026778, A026779. Sequence in context: A026667 A295359 A104208 * A007136 A145974 A147544 Adjacent sequences:  A026774 A026775 A026776 * A026778 A026779 A026780 KEYWORD nonn AUTHOR STATUS approved

Lookup | Welcome | Wiki | Register | Music | Plot 2 | Demos | Index | Browse | More | WebCam
Contribute new seq. or comment | Format | Style Sheet | Transforms | Superseeker | Recents
The OEIS Community | Maintained by The OEIS Foundation Inc.

Last modified August 7 10:19 EDT 2022. Contains 355985 sequences. (Running on oeis4.)