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 A026530 a(n) = T(n, floor(n/2)), T given by A026519. 21
 1, 1, 1, 2, 5, 8, 16, 28, 65, 111, 251, 436, 1016, 1763, 4117, 7176, 16913, 29521, 69865, 122182, 290455, 508595, 1212905, 2126312, 5085224, 8923136, 21389824, 37563930, 90226449, 158563368, 381519416, 670893296, 1616684241, 2844444761 (list; graph; refs; listen; history; text; internal format)
 OFFSET 0,4 LINKS G. C. Greubel, Table of n, a(n) for n = 0..1000 FORMULA a(n) = A026519(n, floor(n/2)). MATHEMATICA T[n_, k_]:= T[n, k]= If[k<0 || k>2*n, 0, If[k==0 || k==2*n, 1, If[k==1 || k==2*n-1, Floor[(n+1)/2], If[EvenQ[n], T[n-1, k-2] + T[n-1, k], T[n-1, k-1] + T[n-1, k-2] + T[n-1, k] ]]]]; (* T = A026519 *) a[n_] := a[n] = Block[{\$RecursionLimit = Infinity}, T[n, Floor[n/2]] ]; Table[a[n], {n, 0, 40}] (* G. C. Greubel, Dec 21 2021 *) PROG (Sage) @CachedFunction def T(n, k): # T = A026519     if (k<0 or k>2*n): return 0     elif (k==0 or k==2*n): return 1     elif (k==1 or k==2*n-1): return (n+1)//2     elif (n%2==0): return T(n-1, k) + T(n-1, k-2)     else: return T(n-1, k) + T(n-1, k-1) + T(n-1, k-2) [T(n, n//2) for n in (0..40)] # G. C. Greubel, Dec 21 2021 CROSSREFS Cf. A026519, A026520, A026521, A026522, A026523, A026524, A026525, A026526, A026527, A026528, A026529, A026531, A026532, A026533, A026534, A027262, A027263, A027264, A027265, A027266. Sequence in context: A301596 A026007 A032233 * A336135 A032254 A323586 Adjacent sequences:  A026527 A026528 A026529 * A026531 A026532 A026533 KEYWORD nonn AUTHOR STATUS approved

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Last modified May 19 23:13 EDT 2022. Contains 353847 sequences. (Running on oeis4.)