A208145 Number of 6Xn 0..1 arrays avoiding 0 0 1 and 0 1 1 horizontally and 0 0 1 and 1 0 1 vertically

12, 144, 756, 3969, 14112, 50176, 141120, 396900, 952560, 2286144, 4889808, 10458756, 20490624, 40144896, 73389888, 134165889, 231891660, 400800400, 661320660, 1091179089, 1731457728, 2747437056, 4216552704, 6471237136

Offset

1,1

Comments

Row 6 of A208142

Links

R. H. Hardin, Table of n, a(n) for n = 1..210

Formula

Empirical: a(n) = 2*a(n-1) +10*a(n-2) -22*a(n-3) -44*a(n-4) +110*a(n-5) +110*a(n-6) -330*a(n-7) -165*a(n-8) +660*a(n-9) +132*a(n-10) -924*a(n-11) +924*a(n-13) -132*a(n-14) -660*a(n-15) +165*a(n-16) +330*a(n-17) -110*a(n-18) -110*a(n-19) +44*a(n-20) +22*a(n-21) -10*a(n-22) -2*a(n-23) +a(n-24).

Empirical: G.f. -x*(12 +120*x +x^23 -2*x^22 -10*x^21 +22*x^20 +44*x^19 -110*x^18 -110*x^17 +330*x^16 +165*x^15 -660*x^14 -132*x^13 +924*x^12 +25*x^11 -794*x^10 +818*x^9 +2110*x^8 +2960*x^7 +3070*x^6 +3910*x^5 +2310*x^4 +1281*x^3 +348*x^2) / ( (1+x)^11*(x-1)^13 ). - R. J. Mathar, Jul 03 2013

Example

Some solutions for n=4
..0..1..0..0....1..0..0..0....0..0..0..0....0..0..0..0....0..0..0..0
..0..1..0..1....0..0..0..0....1..1..0..0....0..1..0..0....0..1..0..0
..0..1..0..1....0..0..0..0....0..0..0..0....0..0..0..0....0..1..0..0
..0..1..0..0....0..0..0..0....0..0..0..0....0..0..0..0....0..1..0..0
..0..0..0..0....0..0..0..0....0..0..0..0....0..0..0..0....0..0..0..0
..0..0..0..0....0..0..0..0....0..0..0..0....0..0..0..0....0..0..0..0

Crossrefs

Sequence in context: A207252 A208290 A208139 * A206937 A188602 A188690

Adjacent sequences: A208142 A208143 A208144 * A208146 A208147 A208148

Keyword

nonn

Author

R. H. Hardin Feb 23 2012

Status

approved