A067959 Number of binary arrangements without adjacent 1's on n X n torus connected ne-sw n-s nw-se.
1, 7, 22, 547, 9021, 812830, 70046159, 24082448515, 10363980496342, 14228018243052057, 29400555005986658803, 166705587265151114516638, 1606507128309318588452521527, 38505096862341023166325442747581, 1696028983502674228038462924646464012
Offset: 1
Examples
Neighbors for n=4 (dots represent spaces): .\|/\|/\|/\|/ . o..o..o..o ./|\/|\/|\/|\ .\|/\|/\|/\|/ . o..o..o..o ./|\/|\/|\/|\ .\|/\|/\|/\|/ . o..o..o..o ./|\/|\/|\/|\ .\|/\|/\|/\|/ . o..o..o..o ./|\/|\/|\/|\
Links
- Sean A. Irvine, Table of n, a(n) for n = 1..17
- V. Kotesovec, Non-attacking chess pieces, 6ed, 2013, p. 73.
Crossrefs
Cf. circle A000204, line A000045, arrays: ne-sw nw-se A067965, e-w ne-sw nw-se A067963, n-s nw-se A067964, e-w n-s nw-se A066864, e-w ne-sw n-s nw-se A063443, n-s A067966, e-w n-s A006506, nw-se A067962, toruses: bare A002416, ne-sw nw-se A067960, e-w ne-sw n-s nw-se A067958, n-s A067961, e-w n-s A027683, e-w ne-sw n-s A066866.
Extensions
a(13) from Vaclav Kotesovec, Aug 22 2016
a(14) from Vaclav Kotesovec, May 24 2021
a(15) from Sean A. Irvine, Jan 14 2024