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 A248449 Number of length 1+5 0..n arrays with no three disjoint pairs in any consecutive six terms having the same sum. 1
 42, 546, 3372, 13500, 41670, 107502, 243576, 499992, 949890, 1695450, 2874852, 4669716, 7313502, 11100390, 16395120, 23643312, 33382746, 46255122, 63018780, 84561900, 111916662, 146273886, 188998632, 241646280, 305979570, 383986122 (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) = 6*a(n-1) - 14*a(n-2) + 14*a(n-3) - 14*a(n-5) + 14*a(n-6) - 6*a(n-7) + a(n-8). Empirical for n mod 2 = 0: a(n) = n^6 + 6*n^5 + (15/2)*n^4 + 20*n^3 + 5*n^2 - 5*n. Empirical for n mod 2 = 1: a(n) = n^6 + 6*n^5 + (15/2)*n^4 + 20*n^3 + 5*n^2 - 5*n + (15/2). Empirical g.f.: 6*x*(7 + 49*x + 114*x^2 + 54*x^3 + 39*x^4 - 23*x^5) / ((1 - x)^7*(1 + x)). - Colin Barker, Nov 08 2018 EXAMPLE Some solutions for n=6: ..2....3....1....3....4....3....1....1....4....0....2....1....0....0....1....0 ..5....1....3....4....2....3....5....1....0....2....2....2....6....0....0....3 ..4....0....5....2....2....1....3....3....3....3....0....5....5....1....5....3 ..4....2....3....3....3....5....2....2....2....2....4....5....3....3....4....0 ..0....2....2....4....2....2....6....0....4....3....3....4....2....1....3....3 ..4....0....2....3....2....3....5....5....3....1....6....0....6....6....1....2 CROSSREFS Row 1 of A248448. Sequence in context: A160065 A196671 A248448 * A245874 A293096 A279888 Adjacent sequences: A248446 A248447 A248448 * A248450 A248451 A248452 KEYWORD nonn AUTHOR R. H. Hardin, Oct 06 2014 STATUS approved

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Last modified September 25 21:50 EDT 2023. Contains 365649 sequences. (Running on oeis4.)