A012049 sec(sin(tanh(x))) = 1+1/2!*x^2-7/4!*x^4+73/6!*x^6+209/8!*x^8...

1, 1, -7, 73, 209, -144271, 16935049, -1681509255, 121927140641, 7429711841377, -7368737635468135, 2672443484700215337, -714451608564077085455, 102412390388191040345041, 45342663705298790615837737, -56227306534265498361644426407

Offset

0,3

Links

Alois P. Heinz, Table of n, a(n) for n = 0..100 (terms n = 0..50 from Vincenzo Librandi)

Mathematica

With[{nn=40}, Take[CoefficientList[Series[Sec[Sin[Tanh[x]]], {x, 0, nn}], x] Range[0, nn]!, {1, -1, 2}]] (* Harvey P. Dale, Sep 25 2013 *)

Crossrefs

Sequence in context: A082719 A188465 A142053 * A012158 A139966 A175205

Adjacent sequences: A012046 A012047 A012048 * A012050 A012051 A012052

Keyword

sign

Author

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

Extensions

More terms from Harvey P. Dale, Sep 25 2013

Status

approved