login
The OEIS is supported by the many generous donors to the OEIS Foundation.

 

Logo
Hints
(Greetings from The On-Line Encyclopedia of Integer Sequences!)
A250814 Number of (2+1) X (n+1) 0..2 arrays with nondecreasing x(i,j)-x(i,j-1) in the i direction and nondecreasing min(x(i,j),x(i-1,j)) in the j direction. 1
129, 379, 873, 1731, 3097, 5139, 8049, 12043, 17361, 24267, 33049, 44019, 57513, 73891, 93537, 116859, 144289, 176283, 213321, 255907, 304569, 359859, 422353, 492651, 571377, 659179, 756729, 864723, 983881, 1114947, 1258689, 1415899 (list; graph; refs; listen; history; text; internal format)
OFFSET
1,1
LINKS
FORMULA
Empirical: a(n) = 1*n^4 + 10*n^3 + 37*n^2 + 54*n + 27.
Conjectures from Colin Barker, Nov 21 2018: (Start)
G.f.: x*(129 - 266*x + 268*x^2 - 134*x^3 + 27*x^4) / (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=4:
..1..1..1..0..0....2..2..1..1..1....1..1..0..0..0....2..1..1..1..1
..0..0..0..1..1....0..1..1..1..1....0..0..0..2..2....1..1..2..2..2
..0..0..1..2..2....0..1..1..1..2....0..0..0..2..2....0..0..1..2..2
CROSSREFS
Row 2 of A250812.
Sequence in context: A235879 A157951 A043383 * A249679 A250750 A036548
KEYWORD
nonn
AUTHOR
R. H. Hardin, Nov 27 2014
STATUS
approved

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

License Agreements, Terms of Use, Privacy Policy. .

Last modified June 20 09:35 EDT 2024. Contains 373515 sequences. (Running on oeis4.)