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 A216940 Number of side-4 hexagonal 0..n arrays with values nondecreasing E, SW and SE. 1
 260, 27768, 1664244, 64697626, 1783839948, 37112483200, 609829326268, 8196058134921, 92610036317488, 899427798281439, 7644907607082576, 57726306147546982, 392120605767310660, 2421735824309042268 (list; graph; refs; listen; history; text; internal format)
 OFFSET 1,1 LINKS R. H. Hardin, Table of n, a(n) for n = 1..37 M. Kauers and C. Koutschan, Some D-finite and some possibly D-finite sequences in the OEIS, arXiv:2303.02793 [cs.SC], 2023. FORMULA 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 EXAMPLE 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 CROSSREFS Row 4 of A216937. Sequence in context: A067639 A264162 A003734 * A200578 A200808 A350084 Adjacent sequences: A216937 A216938 A216939 * A216941 A216942 A216943 KEYWORD nonn AUTHOR R. H. Hardin, Sep 20 2012 STATUS approved

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Last modified June 24 01:53 EDT 2024. Contains 373661 sequences. (Running on oeis4.)