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A211103
a(n) is 1/4 the number of (n+1) X (n+1) 0..3 symmetric matrices with every 2 X 2 subblock having one or three distinct values.
0
7, 121, 5011, 493189, 116069407, 65255935753, 87660979427131, 281363248472730805, 2157777098414728716343, 39538807262703057593016241
OFFSET
1,1
EXAMPLE
Some solutions for n=3:
1 2 0 3 2 3 2 0 3 1 3 2 3 2 1 1 1 1 2 2
2 0 1 1 3 0 3 2 1 2 3 0 2 1 0 3 1 1 3 0
0 1 2 0 2 3 1 2 3 3 1 0 1 0 2 3 2 3 0 1
3 1 0 1 0 2 2 0 2 0 0 2 1 3 3 1 2 0 1 2
CROSSREFS
Sequence in context: A094088 A012043 A316730 * A012103 A012086 A074487
KEYWORD
nonn,more
AUTHOR
R. H. Hardin, Mar 31 2012
STATUS
approved