Number of necklaces with n white beads and 3*n black beads.
A261497
Number of necklaces with n white beads and 3*n black beads.
Terms
- a(0) =1a(1) =1a(2) =4a(3) =19a(4) =116a(5) =776a(6) =5620a(7) =42288a(8) =328756a(9) =2615104a(10) =21191904a(11) =174303163a(12) =1451430692a(13) =12211799224a(14) =103655949072a(15) =886568153744
External references
- oeis: A261497