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A212839 Number of 0..n arrays of length 6 with 0 never adjacent to n. 1
2, 239, 2258, 10727, 35954, 97127, 226274, 472943, 909602, 1637759, 2794802, 4561559, 7170578, 10915127, 16158914, 23346527, 33014594, 45803663, 62470802, 83902919, 111130802, 145343879, 187905698, 240370127, 304498274, 382276127 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

COMMENTS

Row 5 of A212835.

LINKS

R. H. Hardin, Table of n, a(n) for n = 1..210

FORMULA

Empirical: a(n) = n^6 + 6*n^5 + 5*n^4 - 12*n^3 - 3*n^2 + 6*n - 1.

Conjectures from Colin Barker, Jul 21 2018: (Start)

G.f.: x*(2 + 225*x + 627*x^2 - 130*x^3 - 12*x^4 + 9*x^5 - x^6) / (1 - x)^7.

a(n) = 7*a(n-1) - 21*a(n-2) + 35*a(n-3) - 35*a(n-4) + 21*a(n-5) - 7*a(n-6) + a(n-7) for n>7.

(End)

EXAMPLE

Some solutions for n=5:

..1....3....2....5....5....1....5....2....4....2....0....2....0....1....0....3

..3....2....1....3....5....2....1....1....3....0....2....5....2....4....4....1

..5....1....4....2....5....3....2....2....3....1....5....4....2....0....3....1

..4....0....2....5....3....2....5....5....2....1....3....3....4....2....1....0

..2....1....2....5....0....3....1....3....1....4....5....3....0....4....5....1

..5....0....0....1....1....2....4....5....0....5....3....2....2....2....2....2

CROSSREFS

Cf. A212835.

Sequence in context: A159280 A013477 A013473 * A225784 A087226 A217972

Adjacent sequences:  A212836 A212837 A212838 * A212840 A212841 A212842

KEYWORD

nonn

AUTHOR

R. H. Hardin, May 28 2012

STATUS

approved

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Last modified July 4 15:43 EDT 2020. Contains 335448 sequences. (Running on oeis4.)