A012749 sech(arctanh(x)*cos(x))=1-1/2!*x^2+9/4!*x^4-225/6!*x^6+6993/8!*x^8...

1, -1, 9, -225, 6993, -592545, 38019993, -7568120833, 704958936737, -307874830583745, 28902473366214185, -31727751790145150113, 1072204316646061940721, -7192967681050724533661025

Offset

0,3

Links

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

Crossrefs

Sequence in context: A063386 A063392 A012831 * A188662 A079727 A251579

Adjacent sequences: A012746 A012747 A012748 * A012750 A012751 A012752

Keyword

sign

Author

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

Status

approved