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A279122

Denominators of coefficients in expansion of 3/(1 + 2 cos(sqrt(x))).

1, 3, 12, 360, 181440, 1814400, 34214400, 130767436800, 10461394944000, 457312407552000, 3649353012264960000, 562000363888803840000, 3409057152380436480000, 5444434725209176080384000000, 152444172305856930250752000000, 18946632843727932759736320000000

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OFFSET

0,2

LINKS

Clark Kimberling, Table of n, a(n) for n = 0..999

EXAMPLE

1/1 + (1/3)x + (1/12)x^2 + (7/360)x^3 + ... ; 1/1, 1/2, 1/12, 7/360, 809/181440, ... = A279122/A279121.

MATHEMATICA

Denominator[CoefficientList[Series[3/(1 + 2 Cos[Sqrt[x]]), {x, 0, 30}], x]]

CROSSREFS

Cf. A279120, A279122.

Sequence in context: A300532 A249940 A132515 * A246957 A381789 A216897