A013506 - OEIS

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A013506

tan(sec(x) - sech(x)) = 2/2!*x^2 + 362/6!*x^6 + 1199762/10!*x^10 ...

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: A062381 A372992 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