a(n) gives the number of conjugacy classes in the permutation group generated by transposition (1 2) and double n-cycle (1 3 5 7 ... 2n-1)(2 4 6 8 ... 2n). This group is a semidirect product formed by a cyclic group acting on an elementary abelian 2-group of rank n by cyclically permuting the factors.
A178752
a(n) gives the number of conjugacy classes in the permutation group generated by transposition (1 2) and double n-cycle (1 3 5 7 ... 2n-1)(2 4 6 8 ... 2n). This group is a semidirect product formed by a cyclic group acting on an elementary abelian 2-group of rank n by cyclically permuting the factors.
Terms
- a(0) =2a(1) =5a(2) =8a(3) =13a(4) =16a(5) =28a(6) =32a(7) =56a(8) =80a(9) =136a(10) =208a(11) =400a(12) =656a(13) =1232a(14) =2240a(15) =4192a(16) =7744a(17) =14728a(18) =27632a(19) =52664a(20) =99968a(21) =190984a(22) =364768a(23) =699760a(24) =1342256a(25) =2582120a(26) =4971248a(27) =9588880a(28) =18512848a(29) =35795104
External references
- oeis: A178752