1315609

Appears in sequences

• Numbers n such that the sum of composites from the smallest prime factor of n to the largest prime factor of n is equal to the sum of squarefree numbers from the smallest prime factor of n to the largest prime factor of n.at n=28A074255
• Products of squares of 2 successive primes.at n=10A166329
• Each term is the smallest positive integer both coprime to all earlier terms of the sequence and with a different number of divisors than all earlier terms. (a(1)=1.)at n=7A175261
• Numbers k such that concat(k, sigma(k)) and concat(sigma(k), k) are both prime.at n=11A284642