A139673 Number of n X n symmetric binary matrices with all row sums 6.

1, 232, 66178, 24243520, 11234051976, 6549149852112, 4762109992158288, 4274712091685443584, 4686484162304929219950, 6209619146419137708859600, 9845751579221258486943505348, 18509102695712474753650903363840, 40904306737052771732376660591663712

Offset

6,2

Links

Andrew Howroyd, Table of n, a(n) for n = 6..25

Crossrefs

Column k=6 of A333157 and row 6 of A188448.

Sequence in context: A207053 A207130 A125850 * A252003 A151629 A301828

Adjacent sequences: A139670 A139671 A139672 * A139674 A139675 A139676

Keyword

nonn

Author

R. H. Hardin, Jun 12 2008

Extensions

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

Status

approved