Number of necklaces with n white beads and 4*n black beads.
A261498
Number of necklaces with n white beads and 4*n black beads.
Terms
- a(0) =1a(1) =1a(2) =5a(3) =31a(4) =245a(5) =2126a(6) =19811a(7) =192130a(8) =1922741a(9) =19692535a(10) =205446630a(11) =2175519380a(12) =23322657491a(13) =252631900236
External references
- oeis: A261498