A162036 Number of n X n symmetric binary arrays with rows, considered as binary numbers, in nondecreasing order, and no more than 2 1's in any row.

2, 5, 12, 28, 71, 186, 507, 1443, 4241, 12895, 40333, 129679, 427455, 1442384, 4975291, 17518890, 62907021, 230104503, 856679290, 3243467627, 12479244341, 48759284806, 193353224018, 777721210211

Offset

1,1

Links

Table of n, a(n) for n=1..24.

Crossrefs

Sequence in context: A326760 A238828 A326761 * A321253 A290073 A232534

Adjacent sequences: A162033 A162034 A162035 * A162037 A162038 A162039

Keyword

nonn

Author

R. H. Hardin Jun 25 2009

Status

approved