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A269437 Number of length-5 0..n arrays with no repeated value greater than the previous repeated value. 1
28, 222, 964, 2995, 7536, 16408, 32152, 58149, 98740, 159346, 246588, 368407, 534184, 754860, 1043056, 1413193, 1881612, 2466694, 3188980, 4071291, 5138848, 6419392, 7943304, 9743725, 11856676, 14321178, 17179372, 20476639, 24261720 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

LINKS

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

FORMULA

Empirical: a(n) = n^5 + 5*n^4 + (17/2)*n^3 + 8*n^2 + (9/2)*n + 1.

Conjectures from Colin Barker, Jan 22 2019: (Start)

G.f.: x*(28 + 54*x + 52*x^2 - 19*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=8:

..2. .3. .5. .5. .2. .7. .6. .3. .8. .3. .7. .2. .1. .8. .6. .8

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

..5. .0. .6. .4. .2. .8. .6. .0. .2. .0. .5. .4. .1. .0. .1. .7

..0. .2. .7. .6. .4. .4. .1. .0. .4. .7. .8. .3. .4. .3. .7. .4

..3. .3. .4. .7. .5. .1. .7. .3. .5. .3. .0. .4. .0. .6. .5. .8

CROSSREFS

Row 5 of A269435.

Sequence in context: A297614 A249710 A269621 * A236355 A133071 A339137

Adjacent sequences:  A269434 A269435 A269436 * A269438 A269439 A269440

KEYWORD

nonn

AUTHOR

R. H. Hardin, Feb 26 2016

STATUS

approved

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Last modified May 14 04:27 EDT 2021. Contains 343872 sequences. (Running on oeis4.)