The number of permutations of n cards in which 2 is the first card hit and 3 the next hit after 2.
A018931
The number of permutations of n cards in which 2 is the first card hit and 3 the next hit after 2.
Terms
- a(0) =0a(1) =1a(2) =2a(3) =12a(4) =72a(5) =480a(6) =3600a(7) =30240a(8) =282240a(9) =2903040a(10) =32659200a(11) =399168000a(12) =5269017600a(13) =74724249600
External references
- oeis: A018931