A206171 Number of 3 X (n+1) 0..3 arrays with every 2 X 2 subblock in a row having an equal number of equal diagonal or equal antidiagonal elements, adjacent rows differing in this number, and new values 0..3 introduced in row major order.

102, 1070, 14182, 196078, 2728486, 38016046, 529805350, 7383933550, 102911463910, 1434302337070, 19990233287398, 278608949740270, 3883043657285542, 54118965415458862, 754269763387561894

Offset

1,1

Comments

Row 2 of A206169.

Links

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

Formula

Empirical: a(n) = 16*a(n-1) - 21*a(n-2) - 120*a(n-3) + 153*a(n-4) + 216*a(n-5) - 243*a(n-6).

Empirical g.f.: 2*x*(51 - 281*x - 398*x^2 + 1938*x^3 + 927*x^4 - 2997*x^5) / ((1 - x)*(1 - 3*x)*(1 - 3*x^2)*(1 - 12*x - 27*x^2)). - Colin Barker, Jun 14 2018

Example

Some solutions for n=4:
  0 0 0 0 0    0 0 0 0 1    0 1 1 1 0    0 0 0 0 0
  0 1 0 2 0    0 2 0 1 2    0 0 1 0 2    0 1 0 1 0
  2 1 3 1 1    1 3 0 1 2    3 3 3 3 1    1 0 1 0 1

Crossrefs

Cf. A206169.

Sequence in context: A371105 A371055 A088805 * A199830 A200452 A204859

Adjacent sequences: A206168 A206169 A206170 * A206172 A206173 A206174

Keyword

nonn

Author

R. H. Hardin, Feb 04 2012

Status

approved