Number of -1..1 circular arrays x(0..n+1) of n+2 elements with zero sums of x(i) and x(i)*x((i+1) mod (n+2)).
A201999
Number of -1..1 circular arrays x(0..n+1) of n+2 elements with zero sums of x(i) and x(i)*x((i+1) mod (n+2)).
Terms
- a(0) =1a(1) =9a(2) =11a(3) =43a(4) =85a(5) =329a(6) =577a(7) =1921a(8) =4115a(9) =14331a(10) =32631a(11) =106527a(12) =262481a(13) =833225a(14) =2118711a(15) =6523351a(16) =17225857a(17) =52322449a(18) =141538657a(19) =424472841a(20) =1171251495a(21) =3484084667a(22) =9746606361a(23) =28817241129a(24) =81509487175a(25) =240107776015a(26) =684814280371
External references
- oeis: A201999