a(n) = denominator(N), where N = 0.246...(2n) is the concatenation of the first n even numbers after decimal point.

A078260

a(n) = denominator(N), where N = 0.246...(2n) is the concatenation of the first n even numbers after decimal point.

Terms

    a(0) =5a(1) =25a(2) =500a(3) =2500a(4) =100000a(5) =25000000a(6) =5000000000a(7) =125000000000

External references