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A205580 E.g.f.: 1/(cos(x) - sin(x)*cosh(x)). 1
1, 1, 3, 14, 81, 596, 5283, 54424, 641281, 8502736, 125240163, 2029253984, 35869368081, 686861235776, 14164446354243, 312963554690944, 7375924232388481, 184700508637993216, 4897149234545267523, 137056511022745378304, 4037684687434825670481 (list; graph; refs; listen; history; text; internal format)
OFFSET

0,3

COMMENTS

Radius of convergence of e.g.f. is |x| < r, where r = 0.678886646361824692... satisfies tan(r) = 1/cosh(r).

LINKS

Vincenzo Librandi, Table of n, a(n) for n = 0..200

FORMULA

a(n) ~ n!/((sin(r)+cos(r)*cosh(r)+sin(r)*sinh(r))*r^(n+1)), where r = 0.678886646... is the root of the equation sin(r)*cosh(r)=cos(r). - Vaclav Kotesovec, Jun 27 2013

EXAMPLE

E.g.f.: A(x) = 1 + x + 3*x^2/2! + 14*x^3/3! + 81*x^4/4! + 596*x^5/5! +...

MATHEMATICA

CoefficientList[Series[1/(Cos[x]-Sin[x]*Cosh[x]), {x, 0, 20}], x]* Range[0, 20]! (* Vaclav Kotesovec, Jun 27 2013 *)

PROG

(PARI) {a(n)=n!*polcoeff(1/(cos(x+x*O(x^n)) -sin(x+x*O(x^n)) *cosh(x+x*O(x^n))), n)}

CROSSREFS

Sequence in context: A292875 A077054 A325219 * A032332 A032080 A291535

Adjacent sequences:  A205577 A205578 A205579 * A205581 A205582 A205583

KEYWORD

nonn

AUTHOR

Paul D. Hanna, Jan 29 2012

STATUS

approved

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Last modified February 25 14:40 EST 2021. Contains 341609 sequences. (Running on oeis4.)