A139680 Number of n X n symmetric binary matrices with no row sum greater than 4.

1, 2, 8, 64, 1024, 28217, 1146419, 62951431, 4451407563, 392447922178, 42102440864054, 5391561047209898, 811314950514676762, 141599096294933832181, 28348376853054890615951, 6448749608634353498219753, 1653216120840296892595307251, 474197636984335589673286631814

Offset: 0

Author

R. H. Hardin, Jun 13 2008

Keywords

• nonn

Links

• Andrew Howroyd, Table of n, a(n) for n = 0..40

Crossrefs

Column k=4 of A334548.

Extensions

Terms a(13) and beyond from Andrew Howroyd, May 08 2020