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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
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
KEYWORD
nonn
AUTHOR
STATUS
approved

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Last modified April 21 23:01 EDT 2024. Contains 371886 sequences. (Running on oeis4.)