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

 Hints (Greetings from The On-Line Encyclopedia of Integer Sequences!)
 A027035 a(n) = Sum_{k=0..n} T(n,n+k), T given by A027023. 3
 1, 2, 5, 14, 39, 112, 323, 932, 2693, 7790, 22565, 65466, 190243, 553748, 1614363, 4713432, 13780841, 40343210, 118243273, 346937614, 1018958151, 2995407840, 8812890391, 25948662684, 76457517949, 225429675606, 665069604713 (list; graph; refs; listen; history; text; internal format)
 OFFSET 0,2 LINKS G. C. Greubel, Table of n, a(n) for n = 0..1000 MAPLE T:= proc(n, k) option remember; if k<3 or k=2*n then 1 else add(T(n-1, k-j), j=1..3) fi end: seq(add(T(n, k), k=n..2*n), n=0..30); # G. C. Greubel, Nov 04 2019 MATHEMATICA T[n_, k_]:= T[n, k]= If[k<3 || k==2*n, 1, Sum[T[n-1, k-j], {j, 3}]]; Table[Sum[T[n, k], {k, n, 2*n}], {n, 0, 30}] (* G. C. Greubel, Nov 04 2019 *) PROG (Sage) @CachedFunction def T(n, k): if (k<3 or k==2*n): return 1 else: return sum(T(n-1, k-j) for j in (1..3)) [sum(T(n, k) for k in (n..2*n)) for n in (0..30)] # G. C. Greubel, Nov 04 2019 CROSSREFS Sequence in context: A201778 A367655 A105641 * A102406 A307754 A151409 Adjacent sequences: A027032 A027033 A027034 * A027036 A027037 A027038 KEYWORD nonn AUTHOR Clark Kimberling 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 April 21 23:01 EDT 2024. Contains 371886 sequences. (Running on oeis4.)