A012840 exp(sec(x)*arctanh(x))=1+x+1/2!*x^2+6/3!*x^3+21/4!*x^4+120/5!*x^5...

1, 1, 1, 6, 21, 120, 765, 5376, 46473, 415104, 4371225, 48143744, 594635613, 7784817664, 110691178325, 1673986906112, 27018807872657, 462531126525952, 8370279766396593, 159859054841331712

Offset

0,4

Links

Table of n, a(n) for n=0..19.

Crossrefs

Sequence in context: A374836 A365880 A251593 * A013320 A056308 A081077

Adjacent sequences: A012837 A012838 A012839 * A012841 A012842 A012843

Keyword

nonn

Author

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

Status

approved