A connected graph G = (V, E) is said to be (a, d)- antimagic if there exist positive integers a, d and a bijection f : E -> {1, 2,..., vertical bar E vertical bar} such that the induced mapping g(f) : V -> N, defined by gf (v) = Sigma f(uv), uv is an element of E(G), is injective and g(f)(V) = {a, a + d,..., a + (vertical bar V vertical bar - 1)d}. Miller and Baca proved that the generalized Petersen graph P(n, 2) is (3n+6/2, 3)-antimagic for n equivalent to 0(mod 4), n >= 8 and conjectured that the generalized Petersen graph P(n, k) is (3n+6/2, 3)-antimagic for even n and 2 <= k <= n/2 - 1 and conjectured that the generalized Petersen graph P(n, k) is (5n+5/2, 2)-antimagic for odd n and 2 <= k <= n/2 - 1. Xu, Yang, Xi and Li proved that the generalized Petersen graph P(n, 3) is (3n+6/2, 3)-antimagic for n equivalent to 0(mod 4), n >= 8. In this paper, we show that the generalized Petersen graph P(n, 5) is (3n+6/2, 3)-antimagic for even n >= 12.
