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A279109
Denominators of coefficients in expansion of 1/(1 + cos(sqrt(x))).
3
2, 8, 48, 5760, 80640, 14515200, 958003200, 1394852659200, 41845579776000, 25609494822912000, 4865804016353280000, 528941518954168320000, 1240896803466478878720000, 1613165844506422542336000000, 609776689223427721003008000000
OFFSET
0,1
COMMENTS
The numerators are the absolute values of the numbers at A089171.
LINKS
FORMULA
(1/2)*A279110.
EXAMPLE
1/2 + (1/8)x + (1/48)x^2 + (17/5760)x^3 + ... ; 1/2, 1/8, 1/48, 17/5760, 31/80640, ... = |A089171|/A279109.
MATHEMATICA
z = 26; t = CoefficientList[Series[1/(1 + Cos[Sqrt[x]]), {x, 0, z}], x];
u = Numerator[t] (* A089171, unsigned *)
Denominator[t] (* A279109 *)
CROSSREFS
Sequence in context: A009751 A356658 A279239 * A355667 A366239 A364592
KEYWORD
nonn,easy,frac
AUTHOR
Clark Kimberling, Dec 07 2016
STATUS
approved