login
The OEIS Foundation is supported by donations from users of the OEIS and by a grant from the Simons Foundation.

 

Logo


Hints
(Greetings from The On-Line Encyclopedia of Integer Sequences!)
A217958 Number of n X 2 arrays of the minimum value of corresponding elements and their horizontal or antidiagonal neighbors in a random 0..2 n X 2 array. 1
3, 17, 77, 343, 1523, 6761, 30013, 133231, 591427, 2625409, 11654477, 51735495, 229659507, 1019483609, 4525598973, 20089627615, 89180048899, 395879967217, 1757354367693, 7801087777591, 34629879796851, 153725814775369 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

COMMENTS

Column 2 of A217964.

LINKS

R. H. Hardin, Table of n, a(n) for n = 1..179

FORMULA

Empirical: a(n) = 4*a(n-1) + 2*a(n-2) - a(n-4).

Empirical g.f.: x*(1 + x)*(3 + 2*x + x^2) / (1 - 4*x - 2*x^2 + x^4). - Colin Barker, Jul 23 2018

EXAMPLE

Some solutions for n=3:

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

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

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

CROSSREFS

Cf. A217964.

Sequence in context: A100233 A015525 A062224 * A093568 A164305 A202247

Adjacent sequences:  A217955 A217956 A217957 * A217959 A217960 A217961

KEYWORD

nonn

AUTHOR

R. H. Hardin, Oct 16 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 March 7 19:49 EST 2021. Contains 341931 sequences. (Running on oeis4.)