85714286

Appears in sequences

• Numbers k such that k^2 is the concatenation of two numbers 3*m and m.at n=0A115534
• a(n) is equal to the number of positive integers m less than or equal to 10^n such that m is not divisible by at least one of the primes 2,5 and is not divisible by at least one of the primes 3,7.at n=6A128957