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A216940
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Number of side-4 hexagonal 0..n arrays with values nondecreasing E, SW and SE.
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1
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260, 27768, 1664244, 64697626, 1783839948, 37112483200, 609829326268, 8196058134921, 92610036317488, 899427798281439, 7644907607082576, 57726306147546982, 392120605767310660, 2421735824309042268
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OFFSET
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1,1
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LINKS
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FORMULA
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a(n) = (1+n)*(2+n)*(3+n)*(4+n)*(5+n)*(6+n)^2*(7+n)^3*(8+n)^2*(9+n)*(10+n)*(11+n)*(12+n)*(13+n)*(15118483615575730790400000 + 37557333457279933473792000*n + 45137854540680193956153600*n^2 + 34829846371335010335540480*n^3 + 19314394347459920710102704*n^4 + 8166353315859794719296864*n^5 + 2726904840964417033376520*n^6 + 735273283907306553706472*n^7 + 162382123713323392711687*n^8 + 29630015361661371290844*n^9 + 4487557575514810132362*n^10 + 564694034848365996336*n^11 + 58900361433618244860*n^12 + 5062226797216352960*n^13 + 354853893929158096*n^14 + 19969728998781072*n^15 + 880856790135603*n^16 + 29345762188932*n^17 + 694580474022*n^18 + 10413780440*n^19 + 74384146*n^20)/221424599279703105635713957232640000000 (conjectured). - Manuel Kauers and Christoph Koutschan, Mar 01 2023
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EXAMPLE
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Some solutions for n=3:
0 0 0 0 0 0 0 0 0 0 0 0
0 0 0 0 0 0 0 0 0 0 0 0 0 0 0
0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0
0 0 0 0 0 0 2 0 0 0 0 0 0 0 0 0 0 0 0 1 2
0 0 0 0 0 3 0 0 0 1 2 3 0 0 0 0 2 2
0 0 0 2 3 0 0 1 2 3 0 0 0 2 3
2 2 2 3 2 2 2 3 1 1 2 3
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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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