388320domain: NAppears in sequencesT(2n+1,n+2), T given by A026780.at n=8A026899Let X,Y,Z be positive integer solutions to X^2 = Sum_{j=0..Y-1} (1+Z*j)^2, where solutions for Y or Z < 1 are excluded. This sequence lists the values for Z sorted by X.at n=13A350888