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 A279311 Denominators of coefficients in expansion of (cos x)/(1 - x - x^2). 2
 1, 1, 2, 2, 24, 24, 720, 720, 4480, 40320, 3628800, 3628800, 479001600, 95800320, 2641766400, 87178291200, 1902071808000, 20922789888000, 6402373705728000, 6402373705728000, 810967336058880000, 143111882833920000, 66117689869271040000, 13223537973854208000 (list; graph; refs; listen; history; text; internal format)
 OFFSET 0,3 LINKS Clark Kimberling, Table of n, a(n) for n = 0..1000 EXAMPLE (1/1) + (1/1)x + (3/2)x^2 + (5/2)x^3 + ... ; 1/1, 1/1, 3/2, 5/2, ... = A279310/A279311. MATHEMATICA z = 30; t =  CoefficientList[Series[Cos[x]/(1 - x - x^2), {x, 0, z}], x]; Numerator[t]   (* A279310 *) Denominator[t] (* A279311 *) CROSSREFS Cf. A279310. Sequence in context: A120065 A250033 A224479 * A248812 A226243 A226979 Adjacent sequences:  A279308 A279309 A279310 * A279312 A279313 A279314 KEYWORD nonn,easy,frac AUTHOR Clark Kimberling, Dec 11 2016 STATUS approved

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Last modified June 6 16:29 EDT 2020. Contains 334828 sequences. (Running on oeis4.)