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A012825 Expansion of e.g.f. of arctan(sec(x)*arcsinh(x)) (odd coefficients only). 0
1, 0, 8, -392, 20096, -1754368, 241340032, -44833033216, 10840711614464, -3348758074142720, 1285112610745352192, -598690046386495291392, 332953969072425739124736, -217949438999618554495500288 (list; graph; refs; listen; history; text; internal format)
OFFSET

0,3

COMMENTS

arctan(sec(x)*arcsinh(x)) = x + 8/5!*x^5 - 392/7!*x^7 + 20096/9!*x^9 ...

LINKS

Table of n, a(n) for n=0..13.

EXAMPLE

a(0) = 1! * (coefficient of x^1 term) = 1.

a(1) = 3! * (coefficient of x^3 term) = 0.

a(2) = 5! * (coefficient of x^5 term) = 8.

MATHEMATICA

With[{nn=30}, Take[CoefficientList[Series[ArcTan[Sec[x]ArcSinh[x]], {x, 0, nn}], x] Range[0, nn-1]!, {2, -1, 2}]] (* Harvey P. Dale, Jul 31 2013 *)

CROSSREFS

Sequence in context: A220799 A220785 A203368 * A221252 A165036 A185254

Adjacent sequences:  A012822 A012823 A012824 * A012826 A012827 A012828

KEYWORD

sign

AUTHOR

Patrick Demichel (patrick.demichel(AT)hp.com)

STATUS

approved

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Last modified June 28 19:10 EDT 2022. Contains 354907 sequences. (Running on oeis4.)