0,2

1/cosh(x*sqrt(2)) = 1 - 2x^2/2! + 20*x^4/4! - 488*x^6/6! +-...

a(n)=(-1)^[n/2]*2^n*A000364(n). - Philippe DELEHAM (kolotoko(AT)wanadoo.fr), Jun 16 2007

Bisection of A009342.

Sequence in context: A012533 A009160 A009252 this_sequence A012340 A103353 A009344

Adjacent sequences: A012813 A012814 A012815 this_sequence A012817 A012818 A012819

sign

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