A280310 Number of nX3 0..2 arrays with no element equal to more than one of its horizontal and vertical neighbors, with the exception of exactly two elements, and with new values introduced in order 0 sequentially upwards.

0, 15, 788, 20274, 415198, 7506237, 125467047, 1986983748, 30245976536, 446674283782, 6440490980290, 91079336462727, 1267501948747806, 17402523729978130, 236196006568440774, 3174051771081117585

Offset

1,2

Comments

Column 3 of A280313.

Links

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

Formula

Empirical: a(n) = 30*a(n-1) -222*a(n-2) -734*a(n-3) +8955*a(n-4) +17679*a(n-5) -93547*a(n-6) -212481*a(n-7) +239184*a(n-8) +1034132*a(n-9) +1156653*a(n-10) -1089108*a(n-11) -5976636*a(n-12) -5117229*a(n-13) +2977569*a(n-14) +11073336*a(n-15) +13515996*a(n-16) -4312494*a(n-17) -13983961*a(n-18) -6912540*a(n-19) -1327035*a(n-20) +13168450*a(n-21) -1804992*a(n-22) -4913097*a(n-23) +761601*a(n-24) -310968*a(n-25) +2250468*a(n-26) -46384*a(n-27) -448224*a(n-28) +213120*a(n-29) -8640*a(n-30) +157440*a(n-31) +4608*a(n-32) -12288*a(n-33) +9216*a(n-34) +4096*a(n-36) for n>38

Example

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

Crossrefs

Cf. A280313.

Sequence in context: A116094 A267754 A317798 * A211104 A279493 A183821

Adjacent sequences: A280307 A280308 A280309 * A280311 A280312 A280313

Keyword

nonn

Author

R. H. Hardin, Dec 31 2016

Status

approved