a(n)! has exactly 10^n trailing zeros (a(n) = -1 if no such number exists).
A173292
a(n)! has exactly 10^n trailing zeros (a(n) = -1 if no such number exists).
Terms
- a(0) =5a(1) =45a(2) =405a(3) =4005a(4) =40010a(5) =400005a(6) =4000005a(7) =40000010a(8) =400000015a(9) =4000000015a(10) =40000000015a(11) =400000000015a(15) =-1a(16) =-1a(17) =-1a(20) =-1
External references
- oeis: A173292