Number of ferrites M_8Y_n that repeat after 6n+40 layers.

Terms

a(0) =0a(1) =2a(2) =4a(3) =10a(4) =19a(5) =44a(6) =76a(7) =150a(8) =251a(9) =432a(10) =686a(11) =1094a(12) =1646a(13) =2498a(14) =3608a(15) =5206a(16) =7301a(17) =10160a(18) =13814a(19) =18718