On the leading constant in the Manin-type conjecture for Campana points by Alec Shute (Klosterneuburg)1. Introduction. The study of Campana points is an emerging area of interest in arithmetic geometry as a way to interpolate between rational and integral points. Campana orbifolds, first introduced in [4] and [5], consist of a variety X and a weighted boundary divisor D of X. The Campana points associated to the orbifold (X, D) can be viewed as rational points of X that are integral with respect to D. In the recent paper [16], Pieropan, Smeets, Tanimoto and Várilly-Alvarado formulate a Manin-type conjecture for the quantitative study of Campana points on Fano Campana orbifolds, which henceforth we shall refer to as the PSTV-A conjecture. The authors establish their conjecture in the special case of vector group compactifications, using the height zeta function method developed by Chambert-Loir and Tschinkel [7], [8].The arithmetic study of Campana points is still in its early stages. Initial results in [2], [22] and [3], which predate the formulation of the PSTV-A conjecture, concern squareful and m-full values of hyperplanes of P n+1 . (We recall that a non-zero integer z is m-full if for any prime p dividing z, we have p m | z, and squareful if it is 2-full.) Following discussions in the Spring 2006 MSRI program on rational and integral points on higherdimensional varieties, Poonen [17] posed the problem of finding the number of coprime integers z 0 , z 1 such that z 0 , z 1 and z 0 + z 1 are all squareful and bounded by B. In the language of the PSTV-A conjecture, this corresponds to counting Campana points on the orbifold (P 1 , D), where D is the divisorUpper and lower bounds for this problem were obtained by Browning and Van Valckenborgh [2], but finding an asymptotic formula remains wide open. Van Valckenborgh [22] considers a higher-dimensional