a(n)= Number of distinct prime divisors (taken together) of numbers of the form 2x^2-1 for x<=10^n.
A143868
a(n)= Number of distinct prime divisors (taken together) of numbers of the form 2x^2-1 for x<=10^n.
Terms
- a(0) =8a(1) =84a(2) =815a(3) =7922a(4) =77250a(5) =759077a(6) =7492588a(7) =74198995a(8) =736401956a(9) =7319543972a(10) =72834161468a(11) =725344237597
External references
- oeis: A143868