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A026134 a(n) = Sum_{k=1..n} T(k, k-1), where T is the array in A026120. 3
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 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,2

LINKS

Table of n, a(n) for n=1..30.

FORMULA

G.f.: z(1-z)M^3, with M the g.f. of the Motzkin numbers (A001006).

CROSSREFS

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.

First differences of A005322.

Cf. A026123.

Sequence in context: A118041 A105073 A002605 * A105696 A074413 A263897

Adjacent sequences:  A026131 A026132 A026133 * A026135 A026136 A026137

KEYWORD

nonn

AUTHOR

Clark Kimberling

EXTENSIONS

a(25) corrected and more terms from Sean A. Irvine, Sep 17 2019

STATUS

approved

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Last modified November 20 20:56 EST 2019. Contains 329347 sequences. (Running on oeis4.)