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A264672
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Number of (n+1) X (4+1) arrays of permutations of 0..n*5+4 with each element having directed index change -1,-1 1,0 -1,-2 -2,-2 or 0,1.
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1
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1, 29, 123, 890, 6851, 43131, 291315, 1980287, 13199209, 88670692, 595721002, 3995710025, 26820625288, 180019819900, 1208161823995, 8108780202591, 54422802858380, 365262503014440, 2451492555516290, 16453389631984472
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OFFSET
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1,2
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COMMENTS
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LINKS
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FORMULA
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Empirical: a(n) = 3*a(n-1) +9*a(n-2) +106*a(n-3) +212*a(n-5) -1161*a(n-6) +560*a(n-7) -3942*a(n-8) -6220*a(n-9) +2684*a(n-10) -18488*a(n-11) +10184*a(n-12) +76448*a(n-13) +97808*a(n-14) +177984*a(n-15) +21920*a(n-16) +647104*a(n-17) +834688*a(n-18) +224000*a(n-19) +513280*a(n-20) -413184*a(n-21) +221952*a(n-22) -379392*a(n-23) +216576*a(n-24) +258048*a(n-25) -73728*a(n-26) for n>27.
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EXAMPLE
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Some solutions for n=4
.12..0..1..9..3....7..0..9..2..3....6..0..1..9..3...12..0..1..2..3
.11..5..2..7..4...12..1..6.14..4...12..5..2..7..4...17.18..6..7..4
.17..6.19..8.13....5.17.19..8.13...16.18.24..8.13....5.23.24..8..9
.10.22.16.24.14...10.11.16.24.18...10.11.23.17.14...10.11.16.13.14
.15.20.21.18.23...15.20.21.22.23...15.20.21.22.19...15.20.21.22.19
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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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