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A013506 tan(sec(x) - sech(x)) = 2/2!*x^2 + 362/6!*x^6 + 1199762/10!*x^10 ... 0
2, 362, 1199762, 19881945722, 1018678051268642, 125201903398211562122, 31486196823329536613622962, 14521097220214080357933048011162, 11334671748951741252208875241156729922, 14082992180269280951672083015859201930825642, 26533369529542348661168440120005660275350301107922 (list; graph; refs; listen; history; text; internal format)
OFFSET

0,1

LINKS

Table of n, a(n) for n=0..10.

MAPLE

seq(coeff(series(tan(sec(x)-sech(x)), x, 100), x, 2+4*n)*(2+4*n)!, n=0..23); # Herman Jamke (hermanjamke(AT)fastmail.fm), Sep 13 2010

MATHEMATICA

With[{nn=50}, Take[CoefficientList[Series[Tan[Sec[x]-Sech[x]], {x, 0, nn}], x] Range[0, nn]!, {3, -1, 4}]] (* Harvey P. Dale, Mar 07 2019 *)

CROSSREFS

Sequence in context: A325629 A062381 A077350 * A013512 A295174 A320445

Adjacent sequences:  A013503 A013504 A013505 * A013507 A013508 A013509

KEYWORD

nonn

AUTHOR

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

EXTENSIONS

More terms from Herman Jamke (hermanjamke(AT)fastmail.fm), Sep 13 2010

Further terms from N. J. A. Sloane, Dec 17 2011

STATUS

approved

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Last modified February 24 22:04 EST 2020. Contains 332216 sequences. (Running on oeis4.)