OFFSET
0,4
LINKS
Alois P. Heinz, Table of n, a(n) for n = 0..150
FORMULA
a(n) = n! * [(x*y)^n] 1/exp(x+x^2/2*(exp(y)-1)) * Sum_{j>=0} x^j/j! * exp(C(j,2)*y).
a(n) = A059443(n,n).
a(n)/n! ~ c * d^n / n, where d = 2.942382880944169398..., c = 0.1111860502273875... . - Vaclav Kotesovec, Aug 02 2016
EXAMPLE
a(3) = 4: 1|123|23, 12|13|23, 12|123|3, 123|13|2.
CROSSREFS
KEYWORD
nonn
AUTHOR
Alois P. Heinz, Jul 31 2016
STATUS
approved