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A281655
Number of 3Xn 0..2 arrays with no element equal to more than one of its horizontal, diagonal or antidiagonal neighbors, with the exception of exactly one element, and with new values introduced in order 0 sequentially upwards.
1
0, 46, 985, 7986, 67884, 519656, 3804074, 27188104, 190081944, 1307551136, 8883115770, 59735869460, 398338301812, 2637611297824, 17360607113512, 113677820297300, 741027989329060, 4811486509126868, 31131965964391810
OFFSET
1,2
COMMENTS
Row 3 of A281653.
LINKS
FORMULA
Empirical: a(n) = 12*a(n-1) -44*a(n-2) +106*a(n-3) -394*a(n-4) +558*a(n-5) -1815*a(n-6) +1258*a(n-7) -3975*a(n-8) +1226*a(n-9) -3167*a(n-10) -2598*a(n-11) +4765*a(n-12) +1286*a(n-13) -710*a(n-14) +3446*a(n-15) +4320*a(n-16) -2580*a(n-17) -2693*a(n-18) +836*a(n-19) -456*a(n-20) -1676*a(n-21) -92*a(n-22) +1000*a(n-23) +316*a(n-24) -160*a(n-25) -64*a(n-26) for n>29
EXAMPLE
Some solutions for n=4
..0..1..0..1. .0..0..1..0. .0..1..0..1. .0..1..1..2. .0..1..0..1
..2..0..2..1. .2..1..1..2. .0..2..1..1. .2..2..1..0. .0..0..2..2
..2..0..1..2. .2..0..1..0. .1..2..0..1. .0..0..1..2. .2..1..1..0
CROSSREFS
Cf. A281653.
Sequence in context: A078427 A002138 A205495 * A280280 A010962 A057465
KEYWORD
nonn
AUTHOR
R. H. Hardin, Jan 26 2017
STATUS
approved