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 A279235 Numerators of coefficients in expansion of 1/(2 - cos(sqrt(x))). 2
 1, -1, 7, -121, 3907, -28963, 15430207, -1619195761, 415698113, -39531606447181, 787393078729637, -329597897026412143, 56485166839707031039, -25018119236152953236111, 17136704858994825564634201, -5470262193930829308041366531, 34416659770990341862308561437707 (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) - (1/2)x + (7/24)x^2 - (121/720)x^3 + ... ; 1/1, -1/2, 7/24, 1/6480, -121/720, ... = A279235/A279236. MATHEMATICA z = 26; t = CoefficientList[Series[1/(2 - Cos[Sqrt[x]]), {x, 0, z}], x]; Numerator[t] (* A279235 *) Denominator[t] (* A279236 *) CROSSREFS Cf. A279236. Sequence in context: A113267 A274267 A012028 * A094088 A012043 A316730 Adjacent sequences: A279232 A279233 A279234 * A279236 A279237 A279238 KEYWORD sign,easy,frac AUTHOR Clark Kimberling, Dec 08 2016 STATUS approved

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Last modified June 4 10:24 EDT 2023. Contains 363121 sequences. (Running on oeis4.)