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

 

Logo

Year-end appeal: Please make a donation to the OEIS Foundation to support ongoing development and maintenance of the OEIS. We are now in our 56th year, we are closing in on 350,000 sequences, and we’ve crossed 9,700 citations (which often say “discovered thanks to the OEIS”).

Hints
(Greetings from The On-Line Encyclopedia of Integer Sequences!)
A270606 T(n,k)=Number of nXnXn triangular 0..k arrays with some element plus some adjacent element totalling k+1 or k-1 exactly once. 12
0, 0, 6, 0, 0, 0, 0, 36, 0, 0, 0, 36, 312, 0, 0, 0, 96, 1716, 8808, 0, 0, 0, 120, 8148, 171576, 443088, 0, 0, 0, 204, 23448, 1728288, 46957788, 44168712, 0, 0, 0, 252, 67788, 13177740, 1008327378, 38923001616, 8708857332, 0, 0, 0, 360, 144252, 70129212 (list; table; graph; refs; listen; history; text; internal format)
OFFSET

1,3

COMMENTS

Table starts

.0.0........0...........0.............0...............0................0

.6.0.......36..........36............96.............120..............204

.0.0......312........1716..........8148...........23448............67788

.0.0.....8808......171576.......1728288........13177740.........70129212

.0.0...443088....46957788....1008327378.....25162747992.....271906503420

.0.0.44168712.38923001616.1749723617976.176610474548304.4288332432901128

LINKS

R. H. Hardin, Table of n, a(n) for n = 1..112

FORMULA

Empirical for row n:

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

n=3: [order 10] for n>17

n=4: [order 18] for n>33

Empirical quasipolynomials for row n:

n=2: polynomial of degree 2 plus a quasipolynomial of degree 0 with period 2 for n>1

n=3: polynomial of degree 5 plus a quasipolynomial of degree 3 with period 2 for n>7

n=4: polynomial of degree 9 plus a quasipolynomial of degree 7 with period 2 for n>15

EXAMPLE

Some solutions for n=4 k=4

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

....0.4......0.1......0.4......0.0......0.0......0.1......0.1......1.1

...0.4.4....3.1.3....1.3.3....4.4.2....0.0.0....0.0.3....0.0.0....1.3.1

..0.0.0.3..1.3.3.4..3.1.1.3..2.0.4.3..0.1.4.2..4.0.1.3..0.4.4.0..0.0.1.3

CROSSREFS

Sequence in context: A339861 A087936 A089804 * A087255 A097606 A201995

Adjacent sequences:  A270603 A270604 A270605 * A270607 A270608 A270609

KEYWORD

nonn,tabl

AUTHOR

R. H. Hardin, Mar 20 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 December 5 09:45 EST 2021. Contains 349543 sequences. (Running on oeis4.)