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

5,2

Links

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

Crossrefs

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

Sequence in context: A049669 A198476 A234778 * A098606 A093276 A184290

Adjacent sequences: A139668 A139669 A139670 * A139672 A139673 A139674

Keyword

nonn

Author

R. H. Hardin, Jun 12 2008

Extensions

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

Status

approved