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A139680
Number of n X n symmetric binary matrices with no row sum greater than 4.
2
1, 2, 8, 64, 1024, 28217, 1146419, 62951431, 4451407563, 392447922178, 42102440864054, 5391561047209898, 811314950514676762, 141599096294933832181, 28348376853054890615951, 6448749608634353498219753, 1653216120840296892595307251, 474197636984335589673286631814
OFFSET
0,2
LINKS
CROSSREFS
Column k=4 of A334548.
Sequence in context: A191572 A191573 A136283 * A153544 A153572 A191574
KEYWORD
nonn
AUTHOR
R. H. Hardin, Jun 13 2008
EXTENSIONS
Terms a(13) and beyond from Andrew Howroyd, May 08 2020
STATUS
approved