A224551 Number of (n+2)X(n+2) 0..1 matrices with each 3X3 subblock idempotent

50, 94, 180, 286, 540, 992, 1668, 2852, 4870, 8086, 13318, 21860, 35536, 57364, 92210, 147516, 234942, 372868, 589854, 930262, 1463134, 2295546, 3593192, 5612308, 8748560, 13611938, 21141762, 32782810

Offset

1,1

Comments

Diagonal of A224559

Links

Table of n, a(n) for n=1..28.

Formula

Empirical: a(n) = 6*a(n-1) -15*a(n-2) +23*a(n-3) -30*a(n-4) +36*a(n-5) -34*a(n-6) +27*a(n-7) -21*a(n-8) +13*a(n-9) -6*a(n-10) +3*a(n-11) -a(n-12) for n>14

Example

Some solutions for n=3
..1..0..0..0..0....1..1..0..0..0....1..0..0..0..0....1..0..0..0..0
..1..0..0..0..0....0..0..0..0..0....0..0..0..0..1....1..0..0..0..1
..1..0..0..0..0....0..0..0..0..1....0..0..0..0..1....0..0..0..0..1
..1..0..0..0..0....0..0..0..0..1....0..0..0..0..1....0..0..0..0..1
..1..0..0..0..0....0..0..0..0..1....0..0..0..0..1....0..0..0..0..1

Crossrefs

Sequence in context: A259670 A138381 A349208 * A262149 A228953 A335480

Adjacent sequences: A224548 A224549 A224550 * A224552 A224553 A224554

Keyword

nonn

Author

R. H. Hardin Apr 10 2013

Status

approved