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 A027075 a(n) = Sum_{k=0..2n} (k+1) * A027052(n, k). 2
 1, 4, 17, 58, 199, 682, 2301, 7654, 25145, 81740, 263407, 842720, 2679935, 8479378, 26713555, 83847748, 262335577, 818473148, 2547289679, 7910433568, 24517303535, 75854736178, 234317624167, 722776320072, 2226565995913 (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<0 or k>2*n then 0 elif k=0 or k=2 or k=2*n then 1 elif k=1 then 0 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 06 2019 MATHEMATICA T[n_, k_]:= T[n, k]= If[k<0 || k>2*n, 0, If[k==0 || k==2 || k==2*n, 1, If[k==1, 0, 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 06 2019 *) PROG (Sage) @CachedFunction def T(n, k): if (k<0 or k>2*n): return 0 elif (k==0 or k==2 or k==2*n): return 1 elif (k==1): return 0 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 06 2019 CROSSREFS Sequence in context: A183924 A255271 A293798 * A202974 A034331 A107278 Adjacent sequences: A027072 A027073 A027074 * A027076 A027077 A027078 KEYWORD nonn AUTHOR Clark Kimberling STATUS approved

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Last modified July 12 14:09 EDT 2024. Contains 374248 sequences. (Running on oeis4.)