117121

Appears in sequences

• Lucky numbers that are concatenations of n with n + 4.at n=12A032654
• Odd numbers k for which 23 is the smallest positive i with Jacobi symbol J(i,k) != 1.at n=20A112079
• a(n) = 4*n^4 + 17*n^2 + 4.at n=13A156701