Number of ways to seat n people around a circular table such that person i is next to person i-1 or i+1 or both.
A120766
Number of ways to seat n people around a circular table such that person i is next to person i-1 or i+1 or both.
Terms
- a(0) =1a(1) =1a(2) =2a(3) =6a(4) =12a(5) =36a(6) =86a(7) =270a(8) =746a(9) =2554a(10) =8032a(11) =29716a(12) =103482a(13) =409242a(14) =1550850a(15) =6508702a(16) =26509428a(17) =117368404a(18) =508962350a(19) =2365560998a(20) =10842378698a(21) =52685516658a(22) =253754085960
External references
- oeis: A120766