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

0,2

Links

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

Crossrefs

Column k=4 of A334548.

Sequence in context: A191572 A191573 A136283 * A153544 A153572 A191574

Adjacent sequences: A139677 A139678 A139679 * A139681 A139682 A139683

Keyword

nonn

Author

R. H. Hardin, Jun 13 2008

Extensions

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

Status

approved