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 A055579 a(n) = binomial(12*n-1,3*n-1)/((6*n-1)*(12*n-1)). 0
 1, 133, 39556, 16112057, 7772368380, 4168218286276, 2403705165816240, 1461462393790971585, 925088518413937893358, 604420266372219374357644, 405139322689963395796890100, 277349882927724253636179972980 (list; graph; refs; listen; history; text; internal format)
 OFFSET 1,2 LINKS C. O. Oakley and R. J. Wisner, Flexagons, Amer. Math. Monthly 64 (1957), 143-154, see p. 151. MATHEMATICA Table[Binomial[12n-1, 3n-1]/((6n-1)(12n-1)), {n, 20}] (* Harvey P. Dale, Nov 02 2011 *) PROG (PARI) a(n) = binomial(12*n-1, 3*n-1)/((6*n-1)*(12*n-1)); \\ Michel Marcus, Sep 29 2017 CROSSREFS Sequence in context: A129049 A281496 A015264 * A191715 A208626 A061491 Adjacent sequences:  A055576 A055577 A055578 * A055580 A055581 A055582 KEYWORD nonn AUTHOR N. J. A. Sloane, Aug 24 2000 STATUS approved

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Last modified December 4 02:40 EST 2021. Contains 349469 sequences. (Running on oeis4.)