Number of permutations of length n with spread 2.
A004206
Number of permutations of length n with spread 2.
Terms
- a(0) =3a(1) =4a(2) =25a(3) =108a(4) =735a(5) =5248a(6) =40824a(7) =362000a(8) =3628185a(9) =39045888a(10) =478988081a(11) =6227101888a(12) =87146087625
External references
- oeis: A004206