Number of 3 X n grids of black and white cells, no 3 of same color vertically or horizontally contiguous.
A060521
Number of 3 X n grids of black and white cells, no 3 of same color vertically or horizontally contiguous.
Terms
- a(0) =6a(1) =36a(2) =102a(3) =378a(4) =1260a(5) =4374a(6) =14946a(7) =51384a(8) =176238a(9) =605022a(10) =2076288a(11) =7126302a(12) =24457806a(13) =83942100a(14) =288096942a(15) =988778082a(16) =3393583068a(17) =11647114446a(18) =39974047290a(19) =137194888728a(20) =470866430838
External references
- oeis: A060521