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A013440 exp(tan(x)-arctan(x))=1+4/3!*x^3-8/5!*x^5+160/6!*x^6+992/7!*x^7... 1
1, 0, 0, 4, 0, -8, 160, 992, -1792, -14464, 484224, 3391232, -30840832, -175044608, 7718963200, 53080130560, -1315838558208, -6862446264320, 426971596029952, 2514483259473920, -136067874243248128 (list; graph; refs; listen; history; internal format)
OFFSET

0,4

MAPLE

A013440 := proc(n)

        exp(tan(x)-arctan(x)) ;

        coeftayl( %, x=0, n) ;

        %*n! ;

end proc: # R. J. Mathar, Dec 16 2011

CROSSREFS

Sequence in context: A152990 A177900 A019249 * A013496 A187172 A081148

Adjacent sequences:  A013437 A013438 A013439 * A013441 A013442 A013443

KEYWORD

sign

AUTHOR

Patrick Demichel (dml(AT)hpfrcu03.france.hp.com)

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Last modified February 14 05:53 EST 2012. Contains 205570 sequences.