A207996 Number of nX7 0..2 arrays with new values 0..2 introduced in row major order and no element equal to any horizontal or vertical neighbor (colorings ignoring permutations of colors).
32, 729, 17749, 441090, 11045757, 277458045, 6978332618, 175605187731, 4419979346851, 111261280858024, 2800819361992659, 70507189155056781, 1774944424628356230, 44682493917576202087, 1124839588414204665607
Offset: 1
Keywords
Examples
Some solutions for n=4 ..0..1..0..2..1..2..0....0..1..2..1..2..0..1....0..1..2..1..2..0..1 ..2..0..1..0..2..1..2....2..0..1..2..0..2..0....1..2..1..2..0..1..2 ..0..1..0..1..0..2..0....0..1..2..1..2..1..2....2..0..2..1..2..0..1 ..2..0..2..0..1..0..1....1..0..1..2..1..2..0....0..1..0..2..0..1..2
Links
- R. H. Hardin, Table of n, a(n) for n = 1..210
Formula
a(n) = 55*a(n-1) -1109*a(n-2) +11330*a(n-3) -67206*a(n-4) +247404*a(n-5) -582440*a(n-6) +881876*a(n-7) -846764*a(n-8) +499200*a(n-9) -172400*a(n-10) +33152*a(n-11) -3264*a(n-12) +128*a(n-13).
G.f.: -x*(32 -1031*x +13142*x^2 -89204*x^3 +360470*x^4 -909704*x^5 +1454814*x^6 -1461492*x^7 +896144*x^8 -320568*x^9 +63472*x^10 -6400*x^11 +256*x^12) / ( -1 +55*x -1109*x^2 +11330*x^3 -67206*x^4 +247404*x^5 -582440*x^6 +881876*x^7 -846764*x^8 +499200*x^9 -172400*x^10 +33152*x^11 -3264*x^12 +128*x^13 ). - R. J. Mathar, Nov 23 2015
Comments