login
This site is supported by donations to The OEIS Foundation.

 

Logo


Hints
(Greetings from The On-Line Encyclopedia of Integer Sequences!)
A219621 Number of n X 2 arrays of the minimum value of corresponding elements and their horizontal or antidiagonal neighbors in a random, but sorted with lexicographically nondecreasing rows and columns, 0..2 n X 2 array. 1
3, 11, 27, 56, 105, 183, 301, 472, 711, 1035, 1463, 2016, 2717, 3591, 4665, 5968, 7531, 9387, 11571, 14120, 17073, 20471, 24357, 28776, 33775, 39403, 45711, 52752, 60581, 69255, 78833, 89376, 100947, 113611, 127435, 142488, 158841, 176567, 195741 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

COMMENTS

Column 2 of A219627.

LINKS

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

FORMULA

Empirical: a(n) = (1/12)*n^4 + (23/12)*n^2 + n.

Conjectures from Colin Barker, Jul 26 2018: (Start)

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

a(n) = 5*a(n-1) - 10*a(n-2) + 10*a(n-3) - 5*a(n-4) + a(n-5) for n>5.

(End)

EXAMPLE

Some solutions for n=3:

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

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

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

CROSSREFS

Cf. A219627.

Sequence in context: A164845 A024194 A011941 * A033960 A147173 A147110

Adjacent sequences:  A219618 A219619 A219620 * A219622 A219623 A219624

KEYWORD

nonn

AUTHOR

R. H. Hardin, Nov 24 2012

STATUS

approved

Lookup | Welcome | Wiki | Register | Music | Plot 2 | Demos | Index | Browse | More | WebCam
Contribute new seq. or comment | Format | Style Sheet | Transforms | Superseeker | Recent
The OEIS Community | Maintained by The OEIS Foundation Inc.

License Agreements, Terms of Use, Privacy Policy. .

Last modified September 20 18:35 EDT 2019. Contains 327245 sequences. (Running on oeis4.)