A231059 Number of nX4 0..3 arrays x(i,j) with each element horizontally or vertically next to at least one element with value (x(i,j)+1) mod 4, no adjacent elements equal, and upper left element zero

0, 20, 208, 2376, 27346, 313944, 3607664, 41448458, 476228082, 5471653976, 62867030958, 722316016670, 8299110691962, 95353331221526, 1095570130851502, 12587645301298246, 144626810987686256, 1661701927233901422

Offset

1,2

Comments

Column 4 of A231063

Links

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

Formula

Empirical: a(n) = 19*a(n-1) -87*a(n-2) -96*a(n-3) +1323*a(n-4) -858*a(n-5) -7666*a(n-6) +7362*a(n-7) +27116*a(n-8) -22605*a(n-9) -65782*a(n-10) +30708*a(n-11) +96872*a(n-12) +33216*a(n-13) -97603*a(n-14) -160311*a(n-15) +74945*a(n-16) +167168*a(n-17) +3832*a(n-18) -42520*a(n-19) -66621*a(n-20) -36551*a(n-21) +42655*a(n-22) +26735*a(n-23) -3326*a(n-24) -4386*a(n-25) -3303*a(n-26) -438*a(n-27) +676*a(n-28) +173*a(n-29) -22*a(n-30) -16*a(n-31)

Example

Some solutions for n=4
..0..1..0..3....0..1..0..1....0..1..2..1....0..3..2..3....0..3..0..1
..3..2..3..2....3..2..1..2....1..2..3..0....1..2..3..0....1..0..3..2
..2..3..0..1....0..1..0..3....0..1..2..1....0..1..2..1....2..1..2..1
..1..2..3..2....3..2..1..0....3..2..3..0....3..2..3..0....3..0..1..0

Crossrefs

Sequence in context: A133070 A135179 A220939 * A161513 A162359 A161880

Adjacent sequences: A231056 A231057 A231058 * A231060 A231061 A231062

Keyword

nonn

Author

R. H. Hardin, Nov 03 2013

Status

approved