a(n) is the number of representative two-color bracelets (necklaces with turnover allowed) with n beads for n >= 2.
A213942
a(n) is the number of representative two-color bracelets (necklaces with turnover allowed) with n beads for n >= 2.
Terms
- a(0) =1a(1) =1a(2) =3a(3) =3a(4) =7a(5) =8a(6) =18a(7) =22a(8) =46a(9) =62a(10) =136a(11) =189a(12) =409a(13) =611a(14) =1344a(15) =2055a(16) =4535a(17) =7154a(18) =15881a(19) =25481a(20) =56533a(21) =92204a(22) =204759a(23) =337593a(24) =748665a(25) =1246862a(26) =2762111a(27) =4636389a(28) =10253938a(29) =17334800
External references
- oeis: A213942