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A199912 Number of -n..n arrays x(0..4) of 5 elements with zero sum, and adjacent elements not equal modulo three (with -1 modulo 3 = 2). 1
14, 82, 256, 804, 1836, 3196, 6064, 10276, 14846, 23154, 34096, 44912, 63114, 85670, 106780, 140664, 181052, 217516, 274204, 339976, 397866, 485814, 585856, 672256, 801254, 945786, 1068792, 1249964, 1450540, 1619260, 1865064, 2134572, 2359126 (list; graph; refs; listen; history; text; internal format)
OFFSET
1,1
COMMENTS
Row 5 of A199909.
LINKS
FORMULA
Empirical: a(n) = a(n-1) +4*a(n-3) -4*a(n-4) -6*a(n-6) +6*a(n-7) +4*a(n-9) -4*a(n-10) -a(n-12) +a(n-13).
Empirical g.f.: 2*x*(7 + 34*x + 87*x^2 + 246*x^3 + 380*x^4 + 332*x^5 + 380*x^6 + 246*x^7 + 87*x^8 + 34*x^9 + 7*x^10) / ((1 - x)^5*(1 + x + x^2)^4). - Colin Barker, May 17 2018
EXAMPLE
Some solutions for n=6:
.-1....4....5....0....2....4...-1...-5....3...-5...-5....0...-6....3....1...-2
..4...-6...-5....2....4...-6...-6....5....2....5....2...-4....4....5....3....6
.-1....4....3....0...-4...-1....5....6...-5....4....3....3...-3....0...-2....1
..3...-3...-2...-2...-5...-2....6...-4....5...-6...-1...-5....5...-2....0...-3
.-5....1...-1....0....3....5...-4...-2...-5....2....1....6....0...-6...-2...-2
CROSSREFS
Cf. A199909.
Sequence in context: A215472 A209942 A215700 * A082971 A176010 A250562
KEYWORD
nonn
AUTHOR
R. H. Hardin, Nov 11 2011
STATUS
approved

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Last modified March 2 21:56 EST 2024. Contains 370498 sequences. (Running on oeis4.)