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A266056
Number of 2Xn integer arrays with each element equal to the number of horizontal and antidiagonal neighbors less than or equal to itself.
1
1, 7, 12, 58, 598, 4427, 26350, 164148, 1074794, 7035874, 45524948, 294270860, 1906419263, 12357270209, 80067019748, 518700090254, 3360509757482, 21772676551545, 141063777857884, 913934658637407, 5921269752932641
OFFSET
1,2
COMMENTS
Row 2 of A266055.
LINKS
FORMULA
Empirical: a(n) = 3*a(n-1) +11*a(n-2) +51*a(n-3) +156*a(n-4) +141*a(n-5) -429*a(n-6) -2785*a(n-7) -5505*a(n-8) -4470*a(n-9) +6355*a(n-10) +33613*a(n-11) +32025*a(n-12) -21483*a(n-13) -43190*a(n-14) -23519*a(n-15) -2201*a(n-16) +16965*a(n-17) +9808*a(n-18) -2953*a(n-19) -715*a(n-20) +1191*a(n-21) -528*a(n-22) -3*a(n-23) +143*a(n-24) -39*a(n-25) +15*a(n-26)
EXAMPLE
Some solutions for n=4
..1..0..1..2....0..3..3..0....0..3..0..2....1..0..2..2....0..2..3..0
..1..3..1..1....0..3..3..0....0..3..0..1....1..3..1..0....2..0..3..0
CROSSREFS
Cf. A266055.
Sequence in context: A192779 A108238 A038278 * A083335 A372734 A358782
KEYWORD
nonn
AUTHOR
R. H. Hardin, Dec 20 2015
STATUS
approved