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

 Year-end appeal: Please make a donation to the OEIS Foundation to support ongoing development and maintenance of the OEIS. We are now in our 60th year, we have over 367,000 sequences, and we’ve reached 11,000 citations (which often say “discovered thanks to the OEIS”). Other ways to Give
 Hints (Greetings from The On-Line Encyclopedia of Integer Sequences!)
 A027043 a(n) = Sum_{k=0..2n} (k+1) * A027023(n,k). 2
 1, 6, 23, 80, 285, 990, 3367, 11256, 37097, 120862, 390123, 1249728, 3978365, 12598350, 39718403, 124743104, 390491505, 1218875302, 3794984883, 11789335464, 36551285573, 113120066678, 349523991123, 1078402178776 (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((k+1)*T(n, k), k=0..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[(k+1)*T[n, k], {k, 0, 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((k+1)*T(n, k) for k in (0..2*n)) for n in (0..30)] # G. C. Greubel, Nov 04 2019 CROSSREFS Sequence in context: A114245 A220238 A078798 * A006815 A264690 A241394 Adjacent sequences: A027040 A027041 A027042 * A027044 A027045 A027046 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 December 11 07:17 EST 2023. Contains 367717 sequences. (Running on oeis4.)