login

Year-end appeal: Please make a donation to the OEIS Foundation to support ongoing development and maintenance of the OEIS. We are now in our 61st year, we have over 378,000 sequences, and we’ve reached 11,000 citations (which often say “discovered thanks to the OEIS”).

A141488
Number of n X n binary matrices, symmetric under 180 degree rotation, with no more than 1 one in any 2 X 2 subblock.
1
1, 2, 1, 7, 14, 111, 277, 4630, 25913, 702227, 6394908, 326629617, 5687827965, 509730678546, 15540557303649, 2543316661538595, 142034694045640208, 41602235282780689163, 4154045153554082019959, 2201424142622929530965310
OFFSET
0,2
LINKS
R. H. Hardin, Aug 09 2008, Table of n, a(n) for n = 0..24
Yüksel Soykan, Sum Formulas for Generalized Fifth-Order Linear Recurrence Sequences, Journal of Advances in Mathematics and Computer Science (2019) Vol. 34, No. 5, 1-14.
CROSSREFS
Sequence in context: A095137 A239104 A260259 * A113042 A305881 A184346
KEYWORD
nonn
AUTHOR
R. H. Hardin, Aug 09 2008
STATUS
approved