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A183906 Number of nondecreasing arrangements of n+2 numbers in 0..3 with each number being the sum mod 4 of two others. 1
2, 5, 17, 38, 67, 105, 153, 212, 283, 367, 465, 578, 707, 853, 1017, 1200, 1403, 1627, 1873, 2142, 2435, 2753, 3097, 3468, 3867, 4295, 4753, 5242, 5763, 6317, 6905, 7528, 8187, 8883, 9617, 10390, 11203, 12057, 12953, 13892, 14875, 15903, 16977, 18098 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

COMMENTS

Column 3 of A183912.

LINKS

R. H. Hardin, Table of n, a(n) for n = 1..199

FORMULA

Empirical: a(n) = (1/6)*n^3 + 2*n^2 + (5/6)*n - 8 for n>2.

Conjectures from Colin Barker, Apr 05 2018: (Start)

G.f.: x*(2 - 3*x + 9*x^2 - 8*x^3 - x^4 + 2*x^5) / (1 - x)^4.

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

(End)

EXAMPLE

All solutions for n=2:

..1....0....0....0....1

..1....0....0....2....2

..2....0....2....2....3

..3....0....2....2....3

CROSSREFS

Cf. A183912.

Sequence in context: A127436 A064168 A118727 * A042361 A114300 A099207

Adjacent sequences:  A183903 A183904 A183905 * A183907 A183908 A183909

KEYWORD

nonn

AUTHOR

R. H. Hardin, Jan 07 2011

STATUS

approved

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Last modified December 11 21:28 EST 2018. Contains 318052 sequences. (Running on oeis4.)