A180764 Half the number of nX4 binary arrays with each element equal to at least one neighbor.

2, 34, 390, 4475, 52186, 606546, 7053923, 82032712, 953982820, 11094190209, 129018028226, 1500393683522, 17448578663219, 202915341402216, 2359770191311572, 27442554696574793, 319138622503858354

Offset: 1

Author

R. H. Hardin Sep 20 2010

Keywords

• nonn

Comments

Column 4 of A180771

Links

• R. H. Hardin, Table of n, a(n) for n=1..99

Formula

Empirical: a(n) = 9*a(n-1) + 35*a(n-2) - 29*a(n-3) - 256*a(n-4) - 120*a(n-5) + 695*a(n-6) + 579*a(n-7) - 949*a(n-8) - 1076*a(n-9) + 485*a(n-10) + 1488*a(n-11) + 588*a(n-12) - 857*a(n-13) - 368*a(n-14) - 73*a(n-15) - 52*a(n-16) + 26*a(n-17) + 14*a(n-18) + 12*a(n-19) - 4*a(n-20)