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 A026702 a(n) = Sum_{k=0..floor(n/2} T(n-k, k), T given by A026692. 2
 1, 1, 2, 3, 5, 8, 15, 26, 48, 79, 137, 223, 403, 689, 1251, 2088, 3647, 6028, 10775, 18386, 33010, 55460, 96916, 161705, 287199, 490430, 873964, 1475256, 2575673, 4325448, 7646036, 13072664, 23169478, 39254755, 68456542 (list; graph; refs; listen; history; text; internal format)
 OFFSET 0,3 LINKS Vincenzo Librandi, Table of n, a(n) for n = 0..1000 MATHEMATICA T[_, 0] = 1; T[n_, n_] = 1; T[n_, k_] /; EvenQ[k] && 1 <= k/2 <= Floor[n/4] || EvenQ[n - k] && 1 <= (n - k)/2 <= Floor[n/4] := T[n, k] = T[n - 1, k - 1] + T[n - 2, k - 1] + T[n - 1, k]; T[n_, k_] := T[n, k] = T[n - 1, k - 1] + T[n - 1, k]; a[n_] := Sum[T[n - k, k], {k, 0, Floor[n/2]}]; Table[a[n], {n, 0, 34}] (* Jean-François Alcover, Jul 02 2017 *) CROSSREFS Sequence in context: A177486 A006982 A054539 * A000047 A101172 A192677 Adjacent sequences:  A026699 A026700 A026701 * A026703 A026704 A026705 KEYWORD nonn AUTHOR STATUS approved

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