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.

7, 121, 5011, 493189, 116069407, 65255935753, 87660979427131, 281363248472730805, 2157777098414728716343, 39538807262703057593016241

Offset

1,1

Links

Table of n, a(n) for n=1..10.

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

Adjacent sequences: A211100 A211101 A211102 * A211104 A211105 A211106

Keyword

nonn,more

Author

R. H. Hardin, Mar 31 2012

Status

approved