A229665 Number of defective 4-colorings of an nX1 0..3 array connected horizontally, antidiagonally and vertically with exactly two mistakes, and colors introduced in row-major 0..3 order

0, 0, 1, 3, 12, 50, 210, 861, 3416, 13140, 49230, 180455, 649572, 2302950, 8060234, 27900705, 95659440, 325241960, 1097691462, 3680494731, 12268315580, 40679151450, 134241199554, 441078226853, 1443528742152, 4707158941500

Offset

1,4

Comments

Column 1 of A229672

Links

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

Formula

Empirical: a(n) = 12*a(n-1) -57*a(n-2) +136*a(n-3) -171*a(n-4) +108*a(n-5) -27*a(n-6) for n>9.

Empirical: g.f. x^3 -x^4*(-3+24*x-77*x^2+114*x^3-72*x^4+18*x^5) / ( (3*x-1)^3*(x-1)^3 ). - R. J. Mathar, Sep 29 2013

Crossrefs

Sequence in context: A180283 A037765 A037653 * A092443 A356280 A108080

Adjacent sequences: A229662 A229663 A229664 * A229666 A229667 A229668

Keyword

nonn

Author

R. H. Hardin, Sep 27 2013

Status

approved