Number of permutations i_1,...,i_n of 1,...,n with i_1 = 1 and i_n = n, and with the n adjacent sums i_1+i_2, i_2+i_3, ..., i_{n-1}+i_n, i_n+i_1 all coprime to n.
A228860
Number of permutations i_1,...,i_n of 1,...,n with i_1 = 1 and i_n = n, and with the n adjacent sums i_1+i_2, i_2+i_3, ..., i_{n-1}+i_n, i_n+i_1 all coprime to n.
Terms
- a(0) =1a(1) =1a(2) =0a(3) =1a(4) =2a(5) =1a(6) =40a(7) =36a(8) =144a(9) =78a(10) =126336a(11) =176a(12) =14035200a(13) =69480a(14) =779436a(15) =25401600a(16) =465334732800a(17) =1700352a(19) =1888106496a(23) =144127475712
External references
- oeis: A228860