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A224551
Number of (n+2)X(n+2) 0..1 matrices with each 3X3 subblock idempotent
0
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
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
KEYWORD
nonn
AUTHOR
R. H. Hardin Apr 10 2013
STATUS
approved