a(n) = (2*5^(2^n) - 1) mod 10^n: a sequence of trimorphic numbers ending in 9.
A224473
a(n) = (2*5^(2^n) - 1) mod 10^n: a sequence of trimorphic numbers ending in 9.
Terms
- a(0) =9a(1) =49a(2) =249a(3) =1249a(4) =81249a(5) =781249a(6) =5781249a(7) =25781249a(8) =425781249a(9) =6425781249a(10) =36425781249a(11) =836425781249
External references
- oeis: A224473