A141050 Number of n X n binary matrices, symmetric about both diagonal and antidiagonal, with rows, considered as binary numbers, in strictly increasing order.

1, 2, 3, 10, 20, 98, 307, 2200, 11253, 122274, 1039587, 17865284, 256702931, 7235318376, 178530216764, 8498781072612, 365328452613008, 30052220838642600

Offset

2,2

Links

Table of n, a(n) for n=2..19.

Crossrefs

Sequence in context: A297872 A298135 A226356 * A354720 A252865 A252868

Adjacent sequences: A141047 A141048 A141049 * A141051 A141052 A141053

Keyword

nonn

Author

R. H. Hardin, Jul 31 2008

Status

approved