589407

Appears in sequences

• Squarefree numbers k such that phi(k) = phi(k+1).at n=21A063739
• Numbers k such that the six numbers 1.prime(k).prime(k+1), prime(k).1.prime(k+1), prime(k).prime(k+1).1, 1.prime(k-1).prime(k), prime(k-1).1.prime(k) and prime(k-1).prime(k).1, where "." denotes concatenation, are primes.at n=0A090871