OFFSET
-2,5
LINKS
G. C. Greubel, Table of n, a(n) for n = -2..100
Eric W. Weisstein, Roman Factorial.
FORMULA
a(n) = n! for n >=0 and ((-1)^(n + 1))/(-n - 1)! for n < 0.
MAPLE
A159333 := n -> ifelse(n < 0, (-1)^(-n - 1)/(-n - 1)!, n!):
seq(A159333(n), n = -2..9); # Peter Luschny, Jun 11 2022
MATHEMATICA
Table[If[n < 0, (-1)^(-n - 1)/(-n - 1)!, n!], {n, -2, 30}] (* G. C. Greubel, Jun 25 2018 *)
PROG
(PARI) for(n=-2, 30, print1(if(n<0, (-1)^(-n - 1)/(-n - 1)!, n!), ", ")) \\ G. C. Greubel, Jun 25 2018
(Magma) [-1, 1] cat [Factorial(n): n in [0..30]]; // G. C. Greubel, Jun 25 2018
CROSSREFS
KEYWORD
easy,sign,less
AUTHOR
Jonathan Vos Post, Apr 10 2009
STATUS
approved