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

 

Logo


Hints
(Greetings from The On-Line Encyclopedia of Integer Sequences!)
A270256 T(n,k)=Number of nXnXn triangular 0..k arrays with some element plus some adjacent element totalling k exactly once. 12
0, 0, 0, 0, 12, 0, 0, 24, 66, 0, 0, 48, 768, 468, 0, 0, 72, 4428, 37848, 3612, 0, 0, 108, 14976, 772056, 3280968, 40020, 0, 0, 144, 42750, 7876728, 308256072, 534438768, 601368, 0, 0, 192, 96768, 51535116, 12712991544, 302595682944, 168922341960 (list; table; graph; refs; listen; history; text; internal format)
OFFSET

1,5

COMMENTS

Table starts

.0.....0.........0............0..............0................0

.0....12........24...........48.............72..............108

.0....66.......768.........4428..........14976............42750

.0...468.....37848.......772056........7876728.........51535116

.0..3612...3280968....308256072....12712991544.....233617868244

.0.40020.534438768.302595682944.67475902622400.4283012188676772

LINKS

R. H. Hardin, Table of n, a(n) for n = 1..98

FORMULA

Empirical for row n:

n=2: a(n) = 2*a(n-1) -2*a(n-3) +a(n-4)

n=3: [order 10]

n=4: [order 18]

Empirical quasipolynomials for row n:

n=2: polynomial of degree 2 plus a quasipolynomial of degree 0 with period 2

n=3: polynomial of degree 5 plus a quasipolynomial of degree 3 with period 2

n=4: polynomial of degree 9 plus a quasipolynomial of degree 7 with period 2

EXAMPLE

Some solutions for n=3 k=4

....0......2......2......2......4......1......3......2......3......0......3

...1.1....1.3....0.0....4.1....4.3....4.0....3.2....2.1....4.3....4.2....1.0

..0.4.4..1.2.0..2.2.1..3.1.2..3.0.2..2.1.0..4.0.1..1.4.2..3.0.3..3.3.4..1.0.2

CROSSREFS

Sequence in context: A242240 A225341 A004012 * A072837 A023917 A230926

Adjacent sequences:  A270253 A270254 A270255 * A270257 A270258 A270259

KEYWORD

nonn,tabl

AUTHOR

R. H. Hardin, Mar 14 2016

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 February 20 22:51 EST 2019. Contains 320362 sequences. (Running on oeis4.)