606056

Appears in sequences

• Triangular array read by rows: T(n,1) = T(n,n) = 1, T(n,k) = 4*T(n-1, k-1) + 2*T(n-1, k).at n=51A119726
• Nonpalindromic positive integers k such that the absolute value of k^2 - reverse(k)^2 is a square.at n=27A256515