OFFSET
0,2
COMMENTS
In the ring of Hurwitz sequences all members have offset 0.
REFERENCES
Xing Gao and William F. Keigher, Interlacing of Hurwitz series, Communications in Algebra, 45:5 (2017), 2163-2185, DOI: 10.1080/00927872.2016.1226885
LINKS
Seiichi Manyama, Table of n, a(n) for n = 0..400
FORMULA
E.g.f. = 1 / Sum_{n >= 0} ((n+1)*(n+2)/2)*x^n/n!.
From Vaclav Kotesovec, Apr 26 2018: (Start)
E.g.f: exp(-x) / (1 + 2*x + x^2/2).
a(n) ~ (-1)^n * n! * exp(2 - sqrt(2)) * (1 + 1/sqrt(2))^(n+1) / sqrt(2).
(End)
MAPLE
# first load Maple commands for Hurwitz operations from link in A302189.
s:=[seq(n*(n+1)/2, n=1..64)];
Hinv(s);
MATHEMATICA
nmax = 20; CoefficientList[Series[1/(E^x*(1 + 2*x + x^2/2)), {x, 0, nmax}], x] * Range[0, nmax]! (* Vaclav Kotesovec, Apr 26 2018 *)
CROSSREFS
KEYWORD
sign
AUTHOR
N. J. A. Sloane and William F. Keigher, Apr 14 2018
STATUS
approved