A271038 Number of 6X6X6 triangular 0..n arrays with some element less than a w, nw or ne neighbor exactly once.

258, 12010, 256020, 3441072, 33505396, 255757328, 1610555756, 8669119882, 40937078274, 172973004078, 664139482668, 2345904959628, 7699860067962, 23679297338148, 68702482342180, 189162014324890, 496732138963680

Offset

1,1

Comments

Row 6 of A271034.

Links

R. H. Hardin, Table of n, a(n) for n = 1..26

Formula

Empirical: a(n) = (3307/154821036883968000)*n^21 + (277057/110586454917120000)*n^20 + (1603411/11585247657984000)*n^19 + (2270033/474249904128000)*n^18 + (30996697/266765571072000)*n^17 + (101572363/48283361280000)*n^16 + (77666311187/2636271525888000)*n^15 + (123014962363/376610217984000)*n^14 + (11598452441/3985293312000)*n^13 + (2030854507051/96566722560000)*n^12 + (2391727070743/19313344512000)*n^11 + (1044262844011/1755758592000)*n^10 + (1225063692125929/527254305177600)*n^9 + (35232199804051/4803701760000)*n^8 + (1481084911939/80061696000)*n^7 + (575071748810329/15692092416000)*n^6 + (2470455323050879/44460928512000)*n^5 + (9812842428469/158336640000)*n^4 + (1957326271199891/41064607584000)*n^3 + (2192821336711/97772875200)*n^2 + (37411763/7759752)*n

Example

Some solutions for n=2
.......0............0............0............0............0............0
......0.0..........0.0..........0.0..........0.1..........0.0..........0.2
.....0.0.0........0.0.1........0.0.0........0.1.1........0.0.0........0.2.2
....0.0.0.1......1.0.1.1......0.0.0.0......0.1.1.1......0.0.0.1......0.0.2.2
...1.1.0.1.1....1.1.2.2.2....1.1.1.1.1....0.2.2.2.1....0.0.1.1.2....1.2.2.2.2
..1.1.1.2.2.2..1.1.2.2.2.2..2.2.1.1.2.2..1.2.2.2.2.2..1.1.1.1.1.2..1.2.2.2.2.2

Crossrefs

Cf. A271034.

Sequence in context: A228998 A219991 A168125 * A097734 A121915 A239655

Adjacent sequences: A271035 A271036 A271037 * A271039 A271040 A271041

Keyword

nonn

Author

R. H. Hardin, Mar 29 2016

Status

approved