A193877 Number of n X n X n triangular 0..6 arrays with no element equal to the difference mod 7 of any two of its neighbors.

7, 216, 3636, 152574, 21331380, 7767784824, 7384820647122, 18209251766239734

Offset

1,1

Links

Table of n, a(n) for n=1..8.

Example

Some solutions for 4 X 4 X 4
.....1........4........2........3........2........1........2........4
....4.4......1.1......2.2......3.3......2.2......1.4......3.2......3.3
...1.4.4....1.1.4....3.3.2....2.2.3....2.2.2....1.1.4....3.2.2....3.3.3
..4.4.1.1..1.1.4.4..3.2.2.2..2.2.3.3..2.2.2.2..4.1.1.4..3.3.2.3..3.2.2.2

Crossrefs

Sequence in context: A045760 A046033 A193836 * A193186 A114939 A193224

Adjacent sequences: A193874 A193875 A193876 * A193878 A193879 A193880

Keyword

nonn

Author

R. H. Hardin, Aug 07 2011

Status

approved