A188820 Number of n X 5 binary arrays without the pattern 0 1 diagonally or antidiagonally.
32, 169, 432, 841, 1360, 2025, 2800, 3721, 4752, 5929, 7216, 8649, 10192, 11881, 13680, 15625, 17680, 19881, 22192, 24649, 27216, 29929, 32752, 35721, 38800, 42025, 45360, 48841, 52432, 56169, 60016, 64009, 68112, 72361, 76720, 81225, 85840, 90601
Offset: 1
Keywords
Examples
Some solutions for 3 X 5: ..1..1..1..1..0....1..1..1..1..1....0..1..0..1..1....0..1..1..1..1 ..0..1..1..0..1....0..1..1..1..0....0..0..0..0..1....1..0..1..1..1 ..1..0..0..1..0....1..0..0..0..0....0..0..0..0..0....0..1..0..0..0
Links
- R. H. Hardin, Table of n, a(n) for n = 1..200
Crossrefs
Cf. A188824.
Formula
Empirical: a(n) = 2*a(n-1) - 2*a(n-3) + a(n-4) for n>5.
Conjectures from Colin Barker, Apr 29 2018: (Start)
G.f.: x*(32 + 105*x + 94*x^2 + 41*x^3 - 16*x^4) / ((1 - x)^3*(1 + x)).
a(n) = 9 - 48*n + 64*n^2 for n even.
a(n) = -48*n + 64*n^2 for n>1 and odd.
(End)
Comments