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A279181 Numerators of coefficients in expansion of 1/(-1 + 2 cos(sqrt(x))). 2
1, 1, 11, 301, 15371, 1261501, 21692333, 2291003591, 5515342166891, 219856146354043, 533289474412481051, 224671379367784281901, 112978424972711121811, 3528028730755504686511279, 46211522130188693681603906171, 5237381988676259999443664085643 (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 + (11/12)x^2 + (301/360)x^3 + ... ; 1/1, 1/1, 11/12, 301/360, ... = A279181/A279182.

MATHEMATICA

z = 26; t = CoefficientList[Series[1/(-1 + 2 Cos[Sqrt[x]]), {x, 0, z}], x];

Numerator[t]   (* A279181 *)

Denominator[t] (* A279182 *)

CROSSREFS

Cf. A279182.

Sequence in context: A101269 A012184 A012027 * A002114 A012192 A012079

Adjacent sequences:  A279178 A279179 A279180 * A279182 A279183 A279184

KEYWORD

nonn,easy,frac

AUTHOR

Clark Kimberling, Dec 08 2016

STATUS

approved

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Last modified October 20 03:04 EDT 2021. Contains 348099 sequences. (Running on oeis4.)