OFFSET
0,3
EXAMPLE
x - 2/2!*x^2 + 4/3!*x^3 - 12/4!*x^4 + 60/5!*x^5 ...
CROSSREFS
KEYWORD
sign
AUTHOR
Patrick Demichel (patrick.demichel(AT)hp.com)
EXTENSIONS
a(0)=0 inserted and title improved by Sean A. Irvine, Aug 01 2018
STATUS
approved