A013008 sech(arctan(x)+tan(x))=1-4/2!*x^2+80/4!*x^4-4384/6!*x^6+451328/8!*x^8...

1, -4, 80, -4384, 451328, -74726784, 18162914304, -6087614197760, 2690808196562944, -1516485688823611392, 1061352718471077658624, -903110171035290053246976, 918161695966849718656434176

Offset

0,2

Links

Table of n, a(n) for n=0..12.

Crossrefs

Sequence in context: A012042 A013139 A013007 * A013180 A322751 A000316

Adjacent sequences: A013005 A013006 A013007 * A013009 A013010 A013011

Keyword

sign

Author

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

Status

approved