A206456 Number of 0..n arrays of length n+2 avoiding the consecutive pattern 0..n.

4, 75, 1016, 15615, 279924, 5764787, 134217712, 3486784383, 99999999980, 3138428376699, 106993205379048, 3937376385699263, 155568095557812196, 6568408355712890595, 295147905179352825824, 14063084452067724990975, 708235345355337676357596, 37589973457545958193355563

Offset: 1

Author

R. H. Hardin, Feb 07 2012

Keywords

• nonn

Links

• R. H. Hardin, Table of n, a(n) for n = 1..210

Crossrefs

Subdiagonal 2 of A206455.

Formula

Empirical: a(n) = Sum_{i=0..floor((n+2)/(n+1))} ((-1)^i*(n+1)^((n+2) -(n+1)*i)*binomial((n+2) -n*i,i)).