A139674 Number of n X n symmetric binary matrices with all row sums 7.

1, 764, 708256, 805036704, 1127512146540, 1966499966796816, 4274712091685443584, 11528251571501588791296, 38295413179145036856212700, 155411811543624388078758718000, 763997249847515085736557734880512, 4511824317564827934662170498445281792

Offset: 7

Author

R. H. Hardin, Jun 12 2008

Keywords

• nonn

Links

• Andrew Howroyd, Table of n, a(n) for n = 7..20

Crossrefs

Column k=7 of A333157 and row 7 of A188448.

Extensions

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