Number of length-n 0..3 arrays connected end-around, with no sequence of L<n elements immediately followed by itself (periodic "squarefree"), and new values introduced in order 0..3.
A215396
Number of length-n 0..3 arrays connected end-around, with no sequence of L<n elements immediately followed by itself (periodic "squarefree"), and new values introduced in order 0..3.
Terms
- a(0) =1a(1) =1a(2) =1a(3) =3a(4) =5a(5) =17a(6) =35a(7) =102a(8) =240a(9) =665a(10) =1661a(11) =4501a(12) =11466a(13) =30366a(14) =78990a(15) =208272a(16) =543065a(17) =1427121a(18) =3733443a(19) =9798235a(20) =25661293a(21) =67307229a(22) =176371866a(23) =462472478
External references
- oeis: A215396