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 A352972 a(n) = Sum_{j=0..2*n} Sum_{k=0..j} A026536(j, k). 2
 1, 6, 35, 204, 1199, 7089, 42070, 250269, 1491262, 8896310, 53118352, 317373194, 1897253203, 11346582851, 67882263130, 406231442387, 2431626954934, 14558306758418, 87177151134954, 522110098886882, 3127380060424476, 18734897945679836, 112245303177542790, 672552484035697364, 4030148584900522009 (list; graph; refs; listen; history; text; internal format)
 OFFSET 0,2 LINKS G. C. Greubel, Table of n, a(n) for n = 0..500 FORMULA a(n) = Sum_{j=0..2*n} Sum_{k=0..j} A026536(j, k). MATHEMATICA T[n_, k_]:= T[n, k]= If[k==0 || k==2*n, 1, If[k==1 || k==2*n-1, Floor[n/2], If[EvenQ[n], T[n-1, k-2] +T[n-1, k-1] +T[n-1, k], T[n-1, k-2] +T[n-1, k]] ]]; A352972[n_]:= A352972[n]= Sum[T[j, k], {j, 0, 2*n}, {k, 0, j}]; Table[A352972[n], {n, 0, 40}] PROG (SageMath) @CachedFunction def T(n, k): # A026536 if k == 0 or k == 2*n: return 1 elif k == 1 or k == 2*n-1: return n//2 elif n % 2 == 1: return T(n-1, k-2) + T(n-1, k) return T(n-1, k-2) + T(n-1, k-1) + T(n-1, k) def A352972(n): return sum(sum(T(j, k) for k in (0..j)) for j in (0..2*n)) [A352972(n) for n in (3..40)] CROSSREFS Cf. A026536, A026550. Sequence in context: A121838 A242629 A001109 * A180033 A354134 A260770 Adjacent sequences: A352969 A352970 A352971 * A352973 A352974 A352975 KEYWORD nonn AUTHOR G. C. Greubel, Apr 12 2022 STATUS approved

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Last modified March 21 06:15 EDT 2023. Contains 361392 sequences. (Running on oeis4.)