a(n) is formed by 2n+1 concatenations of the digit 2r+1 where n=r (mod 5).
A158859
a(n) is formed by 2n+1 concatenations of the digit 2r+1 where n=r (mod 5).
Terms
- a(0) =1a(1) =333a(2) =55555a(3) =7777777a(4) =999999999a(5) =11111111111
External references
- oeis: A158859