a(1) = 1, a(n) = the largest prime divisor of concatenation of sequence (n,n-1,..,2,1,2,..,n-1,n) A007942.
A074836
a(1) = 1, a(n) = the largest prime divisor of concatenation of sequence (n,n-1,..,2,1,2,..,n-1,n) A007942.
Terms
- a(0) =1a(1) =53a(2) =353a(3) =2160617a(4) =479a(5) =146053847a(6) =18533465459a(7) =18588601a(8) =444444443
External references
- oeis: A074836