Number of length n arrays x(i), i=1..n with x(i) in 0..i and no value appearing more than 2 times.
A248836
Number of length n arrays x(i), i=1..n with x(i) in 0..i and no value appearing more than 2 times.
Terms
- a(0) =1a(1) =2a(2) =6a(3) =22a(4) =96a(5) =482a(6) =2736a(7) =17302a(8) =120576a(9) =917762a(10) =7574016a(11) =67354582a(12) =642041856a(13) =6530291042a(14) =70589700096a(15) =808090395862
External references
- oeis: A248836