OFFSET
0,3
FORMULA
MAPLE
gf := exp(1 - 1/(2*x + 1))/(2*x + 1): ser := series(gf, x, 32):
seq(n!*coeff(ser, x, n), n=0..20);
# Alternative:
a := proc(n) option remember; if n < 2 then 1 - n else
4*(1 - n)*((n - 1)*a(n - 2) + a(n - 1)) fi end: seq(a(n), n=0..20);
CROSSREFS
KEYWORD
sign
AUTHOR
Peter Luschny, Jan 19 2020
STATUS
approved