A274732 Number of 7Xn 0..2 arrays with no element equal to any value at offset (-1,-2) (-2,-1) or (-1,0) and new values introduced in order 0..2.

32, 1296, 16524, 301784, 5634776, 105328812, 1980677448, 37188898120, 699226867860, 13139454740876, 246989200003420, 4642070954166124, 87252983103535936, 1639953977382243676, 30824192792654598004

Offset: 1

Author

R. H. Hardin, Jul 03 2016

Keywords

• nonn

Comments

Row 7 of A274728.

Examples

			Some solutions for n=3
..0..1..0. .0..1..0. .0..1..0. .0..0..0. .0..1..0. .0..1..0. .0..0..0
..2..0..1. .1..2..1. .2..0..2. .1..2..1. .1..2..2. .1..0..2. .1..2..1
..0..1..0. .2..1..2. .1..1..0. .0..1..2. .0..1..0. .0..2..0. .2..1..2
..2..0..2. .1..0..0. .2..0..2. .2..0..1. .2..0..1. .1..0..1. .1..2..0
..0..2..0. .2..1..2. .0..2..0. .0..1..0. .0..1..0. .2..1..0. .2..1..2
..2..0..1. .0..0..1. .2..0..2. .1..0..2. .2..0..2. .0..2..1. .1..2..1
..1..1..0. .1..1..2. .1..1..0. .0..2..0. .1..2..0. .2..0..2. .0..1..0
		

Links

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

Crossrefs

Cf. A274728.

Formula

Empirical: a(n) = 21*a(n-1) +46*a(n-2) -2078*a(n-3) +7099*a(n-4) +30390*a(n-5) -199330*a(n-6) +32493*a(n-7) +1799239*a(n-8) -2883655*a(n-9) -6458651*a(n-10) [phone]*a(n-11) +4488011*a(n-12) -63185111*a(n-13) [phone]*a(n-14) [phone]*a(n-15) -147528893*a(n-16) [phone]*a(n-17) [phone]*a(n-18) -172813699*a(n-19) [phone]*a(n-20) [phone]*a(n-21) -135277945*a(n-22) [phone]*a(n-23) -13939351*a(n-24) -6667960*a(n-25) +1422372*a(n-26) +709307*a(n-27) -229702*a(n-28) +8892*a(n-29) +1296*a(n-30) for n>34