90205

Appears in sequences

• Number of primitive (period n) periodic palindromic structures using exactly four different symbols.at n=19A056521
• Triangle read by rows: T(n,k) (0 <= k <= floor(n/2)) is the number of Delannoy paths of length n, having k EE's crossing the line y = x (i.e., two consecutive E steps from the line y = x+1 to the line y = x-1).at n=27A110121
• Least k > 1 such that n*(k*n-1) - 1 divides n^(k*n-1) - 1, or 0 if no such k exists.at n=11A273772