A250740 Number of (n+1) X (6+1) 0..1 arrays with nondecreasing x(i,j)-x(i,j-1) in the i direction and nonincreasing x(i,j)-x(i-1,j) in the j direction.
130, 134, 142, 158, 190, 254, 382, 638, 1150, 2174, 4222, 8318, 16510, 32894, 65662, 131198, 262270, 524414, 1048702, 2097278, 4194430, 8388734, 16777342, 33554558, 67108990, 134217854, 268435582, 536871038, 1073741950, 2147483774, 4294967422
Offset: 1
Keywords
Examples
Some solutions for n=4: ..0..0..0..0..0..0..0....0..1..1..1..0..0..0....0..1..1..0..0..0..1 ..0..0..0..0..0..0..0....0..1..1..1..0..0..0....0..1..1..0..0..0..1 ..0..0..0..0..0..0..0....0..1..1..1..0..0..0....0..1..1..0..0..0..1 ..1..1..1..1..1..1..1....0..1..1..1..0..0..0....0..1..1..0..0..0..1 ..1..1..1..1..1..1..1....0..1..1..1..0..0..0....0..1..1..0..0..0..1
Links
- R. H. Hardin, Table of n, a(n) for n = 1..210
Crossrefs
Column 6 of A250742.
Formula
Empirical: a(n) = 3*a(n-1) - 2*a(n-2); a(n) = 2^(n+1) + 126.
Empirical g.f.: 2*x*(65 - 128*x) / ((1 - x)*(1 - 2*x)). - Colin Barker, Nov 17 2018