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A245949 Number of length n+3 0..7 arrays with some pair in every consecutive four terms totalling exactly 7. 1
2216, 13064, 73728, 397504, 2217096, 12257032, 67596992, 373997376, 2066660136, 11420014856, 63122102528, 348845096320, 1927940409608, 10655229621512, 58887811241024, 325454196462720, 1798683415254952, 9940745874984456 (list; graph; refs; listen; history; text; internal format)
OFFSET
1,1
LINKS
FORMULA
Empirical: a(n) = 3*a(n-1) + 9*a(n-2) + 31*a(n-3) - 19*a(n-4) - 3*a(n-5) - 5*a(n-6) + a(n-7).
Empirical g.f.: 8*x*(277 + 802*x + 1824*x^2 - 1244*x^3 - 231*x^4 - 312*x^5 + 64*x^6) / (1 - 3*x - 9*x^2 - 31*x^3 + 19*x^4 + 3*x^5 + 5*x^6 - x^7). - Colin Barker, Nov 05 2018
EXAMPLE
Some solutions for n=3:
..5....4....0....5....0....4....3....5....6....2....4....6....5....3....7....3
..3....1....1....2....2....1....2....4....1....4....3....2....0....4....2....5
..2....6....7....3....3....3....6....1....2....7....0....3....7....1....4....3
..5....5....2....3....5....5....1....6....5....0....7....1....6....0....5....2
..4....0....5....4....3....4....7....3....5....2....6....4....5....7....3....4
..0....1....6....6....2....3....1....2....6....4....6....7....0....4....7....2
CROSSREFS
Column 7 of A245950.
Sequence in context: A183831 A234867 A234862 * A223159 A223158 A241963
KEYWORD
nonn
AUTHOR
R. H. Hardin, Aug 08 2014
STATUS
approved

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Last modified July 14 19:09 EDT 2024. Contains 374323 sequences. (Running on oeis4.)