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A267473 Number of length-5 0..n arrays with no following elements larger than the first repeated value. 1
21, 160, 712, 2285, 5921, 13216, 26440, 48657, 83845, 137016, 214336, 323245, 472577, 672680, 935536, 1274881, 1706325, 2247472, 2918040, 3739981, 4737601, 5937680, 7369592, 9065425, 11060101, 13391496, 16100560, 19231437, 22831585 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

COMMENTS

Row 5 of A267471.

LINKS

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

FORMULA

Empirical: a(n) = n^5 + (37/12)*n^4 + (11/2)*n^3 + (77/12)*n^2 + 4*n + 1.

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

G.f.: x*(21 + 34*x + 67*x^2 - 7*x^3 + 6*x^4 - x^5) / (1 - x)^6.

a(n) = 6*a(n-1) - 15*a(n-2) + 20*a(n-3) - 15*a(n-4) + 6*a(n-5) - a(n-6) for n>6.

(End)

EXAMPLE

Some solutions for n=7:

..7....1....4....4....7....0....0....7....1....2....4....7....5....6....3....4

..4....0....6....3....7....6....1....2....5....4....4....1....6....1....7....6

..4....1....7....1....7....3....7....4....1....5....2....4....1....4....7....3

..0....3....4....7....1....2....0....1....2....2....1....7....3....7....3....5

..2....6....4....5....5....7....3....1....4....5....4....2....7....7....5....5

CROSSREFS

Cf. A267471.

Sequence in context: A180374 A108675 A296832 * A179097 A070315 A242191

Adjacent sequences:  A267470 A267471 A267472 * A267474 A267475 A267476

KEYWORD

nonn

AUTHOR

R. H. Hardin, Jan 15 2016

STATUS

approved

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Last modified January 28 03:34 EST 2020. Contains 331315 sequences. (Running on oeis4.)