OFFSET
0,4
LINKS
Robert Israel, Table of n, a(n) for n = 0..450
FORMULA
a(n) ~ c * n^(n-5/2) / exp(n), where c = 35.33624296996624315241349866820530476... . - Vaclav Kotesovec, Oct 04 2016
MAPLE
f:= gfun:-rectoproc({a(n) = (n-3)*a(n-1) + (n-1)*a(n-3), a(0) = 1, a(1) = 1, a(2) = 1}, a(n), remember):
map(f, [$0..30]); # Robert Israel, Nov 08 2016
MATHEMATICA
RecurrenceTable[{a[n+1]==(n-2)*a[n]+n*a[n-2], a[0]==1, a[1]==1, a[2]==1}, a, {n, 0, 15}]
PROG
(C) int seq(int n) {int v = 1; if(n <= 2) {v = 1; } else {v = (n-3)*seq(n-1) + (n-1)*seq(n-3); }return v; }
CROSSREFS
KEYWORD
nonn
AUTHOR
Christopher C. Capobianco, Sep 13 2016
STATUS
approved