A196142 Number of nX4 0..4 arrays with each element x equal to the number its horizontal and vertical neighbors equal to 3,0,4,1,2 for x=0,1,2,3,4

5, 17, 26, 83, 168, 346, 865, 2055, 4745, 10866, 24967, 57786, 134514, 312597, 722915, 1670991, 3869674, 8969607, 20789120, 48159310, 111529135, 258315343, 598428365, 1386426078, 3211799633, 7440009880, 17234511484, 39924363651, 92487922123

Offset

1,1

Comments

Every 0 is next to 0 3's, every 1 is next to 1 0's, every 2 is next to 2 4's, every 3 is next to 3 1's, every 4 is next to 4 2's

Column 4 of A196146

Links

Table of n, a(n) for n=1..29.

Formula

Empirical: a(n) = 5*a(n-1) -9*a(n-2) +9*a(n-3) -8*a(n-4) +12*a(n-5) -20*a(n-6) -a(n-7) +21*a(n-8) +5*a(n-9) -11*a(n-10) -60*a(n-11) +128*a(n-12) +17*a(n-13) -20*a(n-14) -77*a(n-15) +15*a(n-16) -15*a(n-17) -28*a(n-18) -32*a(n-19) -118*a(n-20) +28*a(n-21) -65*a(n-22) -17*a(n-23) -22*a(n-24) +12*a(n-25) -15*a(n-26) +3*a(n-28)

Example

Some solutions for n=5
.0.1.3.1...0.1.1.0...0.1.3.1...1.0.0.1...0.0.0.1
.0.1.1.0...1.1.1.1...0.1.1.0...1.1.1.1...0.0.0.1
.1.3.1.0...1.0.0.1...1.3.3.1...0.1.1.0...1.1.1.3
.1.3.1.0...1.1.1.1...3.1.1.1...0.1.1.0...1.1.1.1
.0.1.3.1...0.1.1.0...1.0.0.0...1.3.1.0...0.0.0.0

Crossrefs

Sequence in context: A117635 A268526 A018447 * A195032 A264618 A271471

Adjacent sequences: A196139 A196140 A196141 * A196143 A196144 A196145

Keyword

nonn

Author

R. H. Hardin Sep 28 2011

Status

approved