An odd composite number N is called a Somer-Lucas d-pseudoprime (with d>=1) if there exists a nondegenerate Lucas sequence U(P, Q) with U_0 = 0, U_1 = 1, D = P^2 - 4Q, such that (N, D) = 1 and the rank appearance of N in the sequence U(P, Q) is (1/a)(N - (D/N)), where (D/N) denotes the Jacobi symbol.

Lucas sequence | pseudoprime