a(1) = 1; for n>1, a(n) = the largest prime divisor of the number C(n) formed from the concatenation of 1,2,3,... up to n.
A075022
a(1) = 1; for n>1, a(n) = the largest prime divisor of the number C(n) formed from the concatenation of 1,2,3,... up to n.
Terms
- a(0) =1a(1) =3a(2) =41a(3) =617a(4) =823a(5) =643a(6) =9721a(7) =14593a(8) =3803a(9) =1234567891a(10) =630803a(11) =2110805449a(12) =869211457
External references
- oeis: A075022