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A026134
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a(n) = Sum_{k=1..n} T(k, k-1), where T is the array in A026120.
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3
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1, 2, 6, 16, 44, 120, 329, 904, 2493, 6898, 19151, 53340, 149019, 417522, 1172979, 3303696, 9326931, 26390070, 74824584, 212565864, 604972998, 1724739940, 4925066567, 14085122376, 40339596755, 115688495806, 332203673142, 955090832416, 2749055259956, 7921280088744
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OFFSET
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1,2
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LINKS
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FORMULA
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G.f.: z(1-z)M^3, with M the g.f. of the Motzkin numbers (A001006).
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CROSSREFS
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T(n, n+2), where T is given by A026148, T(n, n-2), where T is the array defined in A026105 and T(n, n+1), where T is given by A026323.
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KEYWORD
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nonn
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AUTHOR
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EXTENSIONS
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STATUS
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approved
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