A281328 Number of 3Xn 0..2 arrays with no element equal to more than one of its horizontal and antidiagonal neighbors, with the exception of exactly one element, and with new values introduced in order 0 sequentially upwards.

0, 28, 1266, 21734, 350818, 5192104, 73653131, 1013236400, 13637005631, 180509743938, 2358417603056, 30491748035452, 390836517507309, 4973595490140238, 62904441991868038, 791409380078261316

Offset

1,2

Comments

Row 3 of A281326.

Links

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

Formula

Empirical: a(n) = 22*a(n-1) -75*a(n-2) -826*a(n-3) +2647*a(n-4) +12524*a(n-5) -31666*a(n-6) -101028*a(n-7) +172228*a(n-8) +478380*a(n-9) -327766*a(n-10) -1371744*a(n-11) -848245*a(n-12) +2223326*a(n-13) +5363769*a(n-14) -723658*a(n-15) -9633470*a(n-16) -5756578*a(n-17) +5497899*a(n-18) +13633286*a(n-19) +3670518*a(n-20) -13409438*a(n-21) -7736445*a(n-22) +6852658*a(n-23) +5255219*a(n-24) -1543628*a(n-25) -2237348*a(n-26) -373776*a(n-27) +751904*a(n-28) +458560*a(n-29) -160320*a(n-30) -151296*a(n-31) +4608*a(n-32) +23552*a(n-33) +11264*a(n-34) -4096*a(n-35) -4096*a(n-36) for n>39

Example

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

Crossrefs

Cf. A281326.

Sequence in context: A092705 A061321 A342894 * A091993 A213692 A118705

Adjacent sequences: A281325 A281326 A281327 * A281329 A281330 A281331

Keyword

nonn

Author

R. H. Hardin, Jan 20 2017

Status

approved