Smallest concatenation 123...(k-1) k (k-1)...321 (a concatenation of natural numbers from 1 to k and back to 1) that is a multiple of 2n-1, or 0 if no such number exists.
A077189
Smallest concatenation 123...(k-1) k (k-1)...321 (a concatenation of natural numbers from 1 to k and back to 1) that is a multiple of 2n-1, or 0 if no such number exists.
Terms
- a(0) =1a(1) =12321a(2) =0a(3) =12345654321a(4) =12321a(5) =121a(6) =12345654321a(7) =0
External references
- oeis: A077189