228091

Appears in sequences

• Number of permutations of length n which avoid the patterns 1243, 2341, 4321.at n=27A116825
• a(n) = Trinomial(2*n+1, 4) = (1/6)*n*(2*n + 1)*(2*n^2 + 9*n + 1), n >= 0.at n=23A302709