A280903 Number of 2Xn 0..2 arrays with no element equal to more than one of its horizontal and antidiagonal neighbors, with the exception of exactly two elements, and with new values introduced in order 0 sequentially upwards.

0, 1, 10, 213, 2292, 21762, 184076, 1457827, 11000888, 80107879, 567420546, 3931417538, 26752272278, 179329108005, 1186930999936, 7770945222145, 50399529101088, 324186782002754, 2070149445768880, 13133990417566391

Offset

1,3

Comments

Row 2 of A280902.

Links

R. H. Hardin, Table of n, a(n) for n = 1..210

Formula

Empirical: a(n) = 15*a(n-1) -57*a(n-2) -88*a(n-3) +651*a(n-4) +333*a(n-5) -2520*a(n-6) -939*a(n-7) +4569*a(n-8) +1456*a(n-9) -4131*a(n-10) -933*a(n-11) +1793*a(n-12) +60*a(n-13) -336*a(n-14) +64*a(n-15) for n>17

Example

Some solutions for n=4
..0..1..2..1. .0..1..2..0. .0..1..2..2. .0..1..1..2. .0..1..2..0
..0..2..2..2. .2..2..0..0. .2..2..0..2. .1..2..2..2. .1..1..1..0

Crossrefs

Cf. A280902.

Sequence in context: A112364 A201621 A057408 * A239770 A239771 A245987

Adjacent sequences: A280900 A280901 A280902 * A280904 A280905 A280906

Keyword

nonn

Author

R. H. Hardin, Jan 10 2017

Status

approved