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A229515
Number of n X 2 0..2 arrays of the median of the corresponding element, the element to the east and the element to the south in a larger (n+1) X 3 0..2 array without adjacent equal elements in the latter.
1
7, 33, 129, 481, 1751, 6433, 23507, 86295, 316099, 1159635, 4251051, 15590219, 57163723, 209618487, 768636943, 2818506063, 10335115437, 37897559703, 138965833325, 509570185111, 1868532243761, 6851675250519, 25124255606589
OFFSET
1,1
COMMENTS
Column 2 of A229521.
LINKS
FORMULA
Empirical: a(n) = 2*a(n-1) + 8*a(n-2) - 7*a(n-3) - 4*a(n-4) + 19*a(n-5) - 17*a(n-6) + 20*a(n-7) - 12*a(n-8) + 17*a(n-9) + 3*a(n-10) + 13*a(n-11) + 16*a(n-12) - 7*a(n-13) + 2*a(n-14) + 8*a(n-15) -1 3*a(n-16) + 9*a(n-17) - 10*a(n-18) - a(n-19) + a(n-20).
EXAMPLE
Some solutions for n=3:
2 0 1 0 2 1 1 2 1 0 1 0 1 1 1 1 1 1 0 1
0 2 1 1 1 0 1 1 1 2 0 1 1 1 2 0 0 2 1 0
2 0 1 2 0 1 0 1 2 0 1 2 1 1 1 2 2 0 0 2
CROSSREFS
Cf. A229521.
Sequence in context: A350643 A114014 A375549 * A320907 A258458 A320546
KEYWORD
nonn
AUTHOR
R. H. Hardin, Sep 25 2013
STATUS
approved