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 A240002 Number of 3 X n 0..3 arrays with no element equal to one plus the sum of elements to its left or two plus the sum of the elements above it or one plus the sum of the elements diagonally to its northwest, modulo 4. 1
 12, 61, 190, 526, 1262, 2766, 5647, 10878, 19971, 35180, 59780, 98414, 157524, 245879, 375214, 560995, 823326, 1188015, 1687817, 2363873, 3267365, 4461408, 6023201, 8046460, 10644157, 13951590, 18129810, 23369432, 29894858, 37968941 (list; graph; refs; listen; history; text; internal format)
 OFFSET 1,1 LINKS R. H. Hardin, Table of n, a(n) for n = 1..210 FORMULA Empirical: a(n) = (1/40320)*n^8 + (1/2016)*n^7 + (7/576)*n^6 + (17/360)*n^5 + (6367/5760)*n^4 - (935/288)*n^3 + (28145/672)*n^2 - (114913/840)*n + 237 for n>6. Conjectures from Colin Barker, Oct 27 2018: (Start) G.f.: x*(12 - 47*x + 73*x^2 + 4*x^3 - 244*x^4 + 558*x^5 - 737*x^6 + 651*x^7 - 375*x^8 + 86*x^9 + 91*x^10 - 128*x^11 + 80*x^12 - 27*x^13 + 4*x^14) / (1 - x)^9. a(n) = 9*a(n-1) - 36*a(n-2) + 84*a(n-3) - 126*a(n-4) + 126*a(n-5) - 84*a(n-6) + 36*a(n-7) - 9*a(n-8) + a(n-9) for n>15. (End) EXAMPLE Some solutions for n=5: ..0..3..3..0..0....0..3..3..0..0....0..0..0..0..3....0..3..3..0..0 ..0..3..3..1..3....0..0..3..1..3....0..3..3..0..0....0..3..2..3..3 ..0..3..3..2..0....0..0..2..1..2....0..0..2..1..3....0..3..1..0..2 CROSSREFS Row 3 of A240000. Sequence in context: A044150 A044531 A304205 * A114241 A127766 A005173 Adjacent sequences:  A239999 A240000 A240001 * A240003 A240004 A240005 KEYWORD nonn AUTHOR R. H. Hardin, Mar 30 2014 STATUS approved

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Last modified May 9 13:42 EDT 2021. Contains 343742 sequences. (Running on oeis4.)