OFFSET
0,8
COMMENTS
a(n) equals the permanent of the n X n matrix with 0's along the main diagonal, the superdiagonal, the subdiagonal, the sub-subdiagonal, the super-superdiagonal, and 1's everywhere else. - John M. Campbell, Jul 09 2011
LINKS
Alois P. Heinz, Table of n, a(n) for n = 0..450
MAPLE
b:= proc(s) option remember; (n-> `if`(n=0, 1, add(
`if`(abs(n-i)>2, b(s minus {i}), 0), i=s)))(nops(s))
end:
a:= n-> b({$1..n}):
seq(a(n), n=0..15); # Alois P. Heinz, Jan 25 2019
MATHEMATICA
a[0] = 1; a[n_] := a[n] = If[n<6, 0, SparseArray[{Band[{1, 1}] -> 0, Band[{2, 1}] -> 0, Band[{3, 1}] -> 0, Band[{1, 2}] -> 0, Band[{1, 3}] -> 0}, {n, n}, 1] // Permanent];
Table[Print[n, " ", a[n]]; a[n], {n, 0, 23}] (* Jean-François Alcover, Apr 30 2019 *)
CROSSREFS
KEYWORD
nonn
AUTHOR
Reiner Martin, Oct 15 2002
EXTENSIONS
More terms from Vladimir Baltic, Vladeta Jovovic, Jan 04 2003
a(21) from Alois P. Heinz, Jul 04 2015
a(22)-a(23) from Alois P. Heinz, Jan 22 2019
a(0)=1 prepended by Alois P. Heinz, Jan 25 2019
STATUS
approved