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 A203184 Number of nX1 0..4 arrays with every nonzero element less than or equal to some horizontal or vertical neighbor 1
 1, 5, 25, 95, 325, 1121, 3985, 14288, 50995, 181336, 644721, 2294193, 8166441, 29066618, 103444256, 368138471, 1310164527, 4662787112, 16594519920, 59058487061, 210183969235, 748026706926, 2662163892493, 9474416502527 (list; graph; refs; listen; history; text; internal format)
 OFFSET 1,2 COMMENTS Column 1 of A203191 LINKS R. H. Hardin, Table of n, a(n) for n = 1..210 FORMULA Empirical: a(n) = 5*a(n-1) -10*a(n-2) +20*a(n-3) -15*a(n-4) +21*a(n-5) -7*a(n-6) +8*a(n-7) -a(n-8) +a(n-9). Empirical g.f.: -x*(1+x^2)*(x^6+6*x^4+9*x^2+1) / ( -1+5*x-10*x^2+20*x^3-15*x^4+21*x^5-7*x^6+8*x^7-x^8+x^9 ). - R. J. Mathar, Jul 02 2013 EXAMPLE Some solutions for n=4 ..2....0....4....0....4....0....2....4....0....0....2....1....0....1....3....2 ..2....1....4....4....4....1....2....4....3....4....4....3....1....2....3....2 ..1....2....1....4....4....4....1....1....4....4....4....4....4....2....2....3 ..0....2....1....4....4....4....0....0....4....4....4....4....4....0....0....3 CROSSREFS Sequence in context: A225011 A228457 A213293 * A073374 A126878 A203340 Adjacent sequences:  A203181 A203182 A203183 * A203185 A203186 A203187 KEYWORD nonn AUTHOR R. H. Hardin, Dec 30 2011 STATUS approved

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Last modified May 16 11:35 EDT 2022. Contains 353704 sequences. (Running on oeis4.)