841376

Appears in sequences

• Indices n of primes p(n), p(n+4) such that p(n)-1 and p(n+4)-1 have the same largest prime factor.at n=28A105407
• G.f. A(x) satisfies A(x) = 1 / (1 - x*A(x) / (1+x))^4.at n=7A371496