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 A165374 Number of slanted n X 5 (i=1..n) X (j=i..5+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, and 4 in the lower right corner. 1
 105, 1622, 11960, 63740, 272548, 993780, 3239860, 9743508, 27593908, 74632788, 194702068, 493466004, 1221540916, 2965389012, 7081701748, 16678011924, 38810916532, 89383135572, 203992087540, 461842419348, 1038214750516 (list; graph; refs; listen; history; text; internal format)
 OFFSET 2,1 LINKS R. H. Hardin, Table of n, a(n) for n=2..48 FORMULA Empirical: a(n) = 8*a(n-1) - 25*a(n-2) + 38*a(n-3) - 28*a(n-4) + 8*a(n-5) for n>=11. Empirical g.f.: x^2*(105 + 782*x + 1609*x^2 + 4620*x^3 + 2932*x^4 - 3008*x^5 + 3104*x^6 + 1344*x^7 + 128*x^8) / ((1 - x)^2*(1 - 2*x)^3). - Colin Barker, Mar 26 2018 EXAMPLE Some solutions for n=3: ...1.2.2.2.2.......1.1.1.2.2.......1.1.2.2.2.......1.1.1.2.2.... .....3.3.3.2.2.......1.1.1.2.4.......1.3.3.2.2.......1.1.1.2.2.. .......3.2.2.2.4.......3.3.2.4.4.......3.3.4.4.4.......3.1.2.4.4 ------ ...1.1.2.2.2.......1.1.1.2.2.......1.1.1.1.2.......1.1.2.2.2.... .....1.1.1.1.1.......1.2.2.2.2.......1.1.1.2.2.......1.1.2.2.2.. .......3.3.3.3.4.......3.3.2.4.4.......3.3.3.4.4.......3.4.4.4.4 ------ ...1.1.2.2.2.......1.1.1.3.2.......1.1.2.2.2.......1.1.2.2.2.... .....1.2.3.2.4.......3.3.3.2.2.......2.2.2.4.4.......2.2.2.4.4.. .......3.3.3.4.4.......3.2.2.4.4.......3.4.4.4.4.......3.2.2.4.4 CROSSREFS Sequence in context: A051015 A221449 A076377 * A024198 A027788 A112497 Adjacent sequences: A165371 A165372 A165373 * A165375 A165376 A165377 KEYWORD nonn AUTHOR R. H. Hardin, Sep 17 2009 STATUS approved

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Last modified July 21 18:17 EDT 2024. Contains 374475 sequences. (Running on oeis4.)