Number of undirected circular permutations pi(1), ..., pi(n) of 1, ..., n with the n numbers pi(1)*pi(2)-1, pi(2)*pi(3)-1, ..., pi(n-1)*pi(n)-1, pi(n)*pi(1)-1 all prime.
A229232
Number of undirected circular permutations pi(1), ..., pi(n) of 1, ..., n with the n numbers pi(1)*pi(2)-1, pi(2)*pi(3)-1, ..., pi(n-1)*pi(n)-1, pi(n)*pi(1)-1 all prime.
Terms
- a(0) =0a(1) =0a(2) =0a(3) =1a(4) =0a(5) =2a(6) =1a(7) =2a(8) =2a(9) =8a(10) =2a(11) =241a(12) =0a(13) =693a(14) =376a(15) =7687a(16) =1082a(17) =127563a(18) =25113a(19) =1353842a(20) =559649
External references
- oeis: A229232