A139671 Number of n X n symmetric binary matrices with all row sums 5.

1, 76, 6912, 848932, 133948836, 26615510712, 6549149852112, 1966499966796816, 711040444591249476, 305907023641901084832, 154921887640109512226304, 91469751377953081098144816, 62419855497729620428436222688, 48849705066296300911892229634944

Offset: 5

Author

R. H. Hardin, Jun 12 2008

Keywords

• nonn

Links

• Andrew Howroyd, Table of n, a(n) for n = 5..25

Crossrefs

Column k=5 of A333157 and row 5 of A188448.

Extensions

Terms a(13) and beyond from Andrew Howroyd, Mar 09 2020