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A222869 Number of n X 3 0..5 arrays with no element equal to another at a city block distance of exactly two, and new values 0..5 introduced in row major order. 1
3, 34, 816, 30528, 1186704, 46269792, 1804486896, 70374883968, 2744620159824, 107040185288352, 4174567223411376, 162808121704540608, 6349516746451574544, 247631153111534879712, 9657614971349630726256, 376646983882634909576448 (list; graph; refs; listen; history; text; internal format)
OFFSET
1,1
COMMENTS
Column 3 of A222871.
LINKS
FORMULA
Empirical: a(n) = 42*a(n-1) - 117*a(n-2) for n>4.
Conjectures from Colin Barker, Aug 16 2018: (Start)
G.f.: x*(3 - 92*x - 261*x^2 + 234*x^3) / ((1 - 3*x)*(1 - 39*x)).
a(n) = 4*3^(n-1) + 20*39^(n-2) for n>2.
(End)
EXAMPLE
Some solutions for n=3:
..0..0..1....0..1..2....0..1..2....0..1..2....0..1..2....0..1..2....0..1..1
..2..2..3....3..3..4....3..3..0....3..4..5....3..1..0....3..4..2....2..3..4
..4..5..5....1..2..5....2..4..1....1..2..3....4..2..5....5..4..0....1..5..5
CROSSREFS
Cf. A222871.
Sequence in context: A231850 A109521 A274744 * A069718 A077144 A222778
KEYWORD
nonn
AUTHOR
R. H. Hardin, Mar 07 2013
STATUS
approved

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Last modified February 23 21:40 EST 2024. Contains 370288 sequences. (Running on oeis4.)