login
A210856
Number of (n+1)X(n+1) 0..2 symmetric matrices with every 2X2 subblock having one or three distinct values, and new values 0..2 introduced in lower triangle row major order
0
2, 7, 52, 653, 13626, 466059, 26123304, 2397815265, 360393055118, 88675989046143, 35717797661887220, 23549404183669259509, 25414418850237694865002
OFFSET
1,1
EXAMPLE
Some solutions for n=3
..0..1..0..2....0..0..1..0....0..1..0..1....0..1..0..1....0..0..1..0
..1..2..0..1....0..0..2..0....1..2..0..2....1..2..1..2....0..0..2..0
..0..0..1..2....1..2..1..0....0..0..1..1....0..1..0..0....1..2..1..1
..2..1..2..0....0..0..0..2....1..2..1..1....1..2..0..0....0..0..1..1
CROSSREFS
Sequence in context: A220092 A138737 A216086 * A046662 A237195 A275597
KEYWORD
nonn
AUTHOR
R. H. Hardin Mar 28 2012
STATUS
approved