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A165379
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Number of slanted nX6 (i=1..n)X(j=i..6+i-1) 1..4 arrays with all 1s connected, all 2s connected, all 3s connected, all 4s connected, 1 in the upper left corner, 2 in the upper right corner, 3 in the lower left corner, 4 in the lower right corner, and with no element having more than 2 neighbors with the same value
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0
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101, 233, 265, 335, 409, 483, 557, 631, 705, 779, 853, 927, 1001, 1075, 1149, 1223
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OFFSET
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2,1
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LINKS
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FORMULA
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Empirical: a(n)=2*a(n-1)-a(n-2) for n>=7
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EXAMPLE
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Some solutions for n=3
...1.1.1.1.2.2.......1.1.2.2.2.2.......1.1.1.1.1.2.......1.1.1.2.2.2....
.....3.3.1.2.4.4.......3.3.4.4.2.2.......3.3.4.1.2.2.......3.3.2.4.2.2..
.......3.3.3.3.4.4.......3.3.4.4.4.4.......3.4.4.4.4.4.......3.2.4.4.4.4
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...1.1.2.2.2.2.......1.1.1.2.2.2.......1.1.4.4.4.2.......1.2.2.2.2.2....
.....1.1.1.4.2.2.......2.2.2.4.4.4.......1.1.1.4.4.4.......2.4.4.4.4.4..
.......3.3.4.4.4.4.......3.3.3.3.4.4.......3.3.3.3.4.4.......3.3.3.3.4.4
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CROSSREFS
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KEYWORD
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nonn
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AUTHOR
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STATUS
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approved
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