47834153641domain: NAppears in sequencesExpansion of g.f. 1/((1-5*x)*(1-7*x)).at n=12A0161616th binomial transform of (0,1,0,1,0,1,...), A000035.at n=13A081200Zsigmondy numbers for a = 7, b = 5: Zs(n, 7, 5) is the greatest divisor of 7^n - 5^n that is relatively prime to 7^m - 5^m for all positive integers m < n.at n=12A109349