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A183910 Number of nondecreasing arrangements of n+2 numbers in 0..7 with each number being the sum mod 8 of two others. 1
2, 5, 40, 207, 778, 2199, 5126, 10501, 19630, 34274, 56754, 90071, 138042, 205453, 298230, 423629, 590446, 809248, 1092626, 1455471, 1915274, 2492451, 3210694, 4097349, 5183822, 6506014, 8104786, 10026455, 12323322, 15054233, 18285174 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

COMMENTS

Column 7 of A183912.

LINKS

R. H. Hardin, Table of n, a(n) for n = 1..61

FORMULA

Empirical: a(n) = (1/5040)*n^7 + (1/120)*n^6 + (53/360)*n^5 + (17/12)*n^4 - (1313/720)*n^3 - (1777/40)*n^2 + (14876/105)*n - 83 for n>3.

Conjectures from Colin Barker, Apr 06 2018: (Start)

G.f.: x*(2 - 11*x + 56*x^2 - 85*x^3 + 102*x^4 - 231*x^5 + 302*x^6 - 129*x^7 - 44*x^8 + 49*x^9 - 10*x^10) / (1 - x)^8.

a(n) = 8*a(n-1) - 28*a(n-2) + 56*a(n-3) - 70*a(n-4) + 56*a(n-5) - 28*a(n-6) + 8*a(n-7) - a(n-8) for n>10.

(End)

EXAMPLE

All solutions for n=2:

..0....2....2....0....0

..0....2....4....0....4

..0....4....6....4....4

..0....6....6....4....4

CROSSREFS

Cf. A183912.

Sequence in context: A155176 A127974 A012801 * A162035 A245242 A004096

Adjacent sequences:  A183907 A183908 A183909 * A183911 A183912 A183913

KEYWORD

nonn

AUTHOR

R. H. Hardin, Jan 07 2011

STATUS

approved

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Last modified October 18 13:41 EDT 2021. Contains 348068 sequences. (Running on oeis4.)