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 A248456 Number of length n+2 0..3 arrays with no three consecutive terms having the sum of any two elements equal to twice the third. 1
 48, 148, 460, 1436, 4488, 14040, 43940, 137532, 430508, 1347652, 4218704, 13206360, 41341772, 129418260, 405137308, 1268262348, 3970233208, 12428621208, 38907193300, 121797075276, 381279818252, 1193577924020, 3736437636672 (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) = 2*a(n-1) + 3*a(n-2) + 4*a(n-3) - 3*a(n-4) - 12*a(n-5) - 4*a(n-6). Empirical g.f.: 4*x*(12 + 13*x + 5*x^2 - 30*x^3 - 53*x^4 - 16*x^5) / (1 - 2*x - 3*x^2 - 4*x^3 + 3*x^4 + 12*x^5 + 4*x^6). - Colin Barker, Nov 08 2018 EXAMPLE Some solutions for n=6: ..0....0....0....1....0....2....2....2....2....3....3....1....2....2....0....2 ..3....1....3....1....3....3....1....0....3....0....3....1....2....2....3....2 ..1....3....1....3....3....0....1....3....3....3....1....0....3....0....2....1 ..3....3....3....0....1....0....3....0....2....0....1....1....0....2....0....1 ..1....1....0....0....0....3....1....2....3....1....2....0....3....3....0....2 ..3....0....3....3....3....3....3....3....3....0....1....0....0....0....2....2 ..1....1....0....0....1....0....1....0....2....3....2....2....0....3....0....1 ..1....3....2....1....0....0....3....0....2....0....2....2....1....0....2....1 CROSSREFS Column 3 of A248461. Sequence in context: A039496 A044380 A044761 * A370126 A346293 A244178 Adjacent sequences: A248453 A248454 A248455 * A248457 A248458 A248459 KEYWORD nonn AUTHOR R. H. Hardin, Oct 06 2014 STATUS approved

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Last modified August 4 04:17 EDT 2024. Contains 374905 sequences. (Running on oeis4.)