A195958 Number of nX4 0..4 arrays with each element equal to the number its horizontal and vertical neighbors unequal to itself.

1, 5, 16, 19, 25, 70, 105, 155, 332, 557, 1043, 1904, 3391, 6117, 11118, 20903, 37963, 69792, 127581, 235413, 434388, 799835, 1483313, 2732560, 5053827, 9336031, 17297902, 32036101, 59311429, 109934878, 203609521, 377642933, 700109674

Offset

1,2

Comments

Column 4 of A195962

Links

R. H. Hardin, Table of n, a(n) for n = 1..200

Formula

Empirical: a(n) = 2*a(n-1) -a(n-2) +7*a(n-3) -5*a(n-4) +3*a(n-5) -23*a(n-6) -4*a(n-7) -51*a(n-8) +40*a(n-9) -44*a(n-10) +231*a(n-11) +25*a(n-12) +372*a(n-13) -129*a(n-14) +18*a(n-15) -498*a(n-16) -468*a(n-17) -675*a(n-18) -619*a(n-19) -458*a(n-20) -66*a(n-21) +550*a(n-22) +678*a(n-23) +1791*a(n-24) +300*a(n-25) +2249*a(n-26) +52*a(n-27) +2665*a(n-28) +12*a(n-29) +473*a(n-30) -897*a(n-31) +518*a(n-32) +419*a(n-33) +646*a(n-34) -136*a(n-35) +896*a(n-36) +2630*a(n-37) -528*a(n-38) +1206*a(n-39) -3946*a(n-40) -8*a(n-41) -3110*a(n-42) -1640*a(n-43) -1168*a(n-44) -1436*a(n-45) +392*a(n-46) -696*a(n-47) +432*a(n-48)

Example

Some solutions for n=5
..1..1..1..2....1..3..2..1....1..1..1..1....1..1..1..1....2..1..1..2
..3..4..1..1....1..4..2..1....2..3..2..2....2..2..4..3....3..1..1..3
..1..1..1..1....1..2..2..1....2..3..2..3....3..2..3..2....1..1..1..1
..1..1..4..3....1..2..4..1....3..4..2..2....2..2..3..2....1..3..3..1
..2..1..1..1....1..2..3..1....1..1..1..1....1..1..1..1....1..2..2..1

Crossrefs

Sequence in context: A298226 A298150 A238586 * A151980 A063612 A269969

Adjacent sequences: A195955 A195956 A195957 * A195959 A195960 A195961

Keyword

nonn

Author

R. H. Hardin, Sep 25 2011

Status

approved