22143375

Appears in sequences

• Numbers n such that Sum_{i=1..j} 1/pn(i) + Sum_{i=1..k} 1/pd(i) is an integer, where pn are the prime factors of n and pd the prime factors of the arithmetic derivative of n, both counted with multiplicity.at n=16A239490
• Number of divisors of the n-th positive number that is both triangular and square.at n=41A242585
• Numbers k such that both k and k+1 are exceptional (A072066).at n=23A331625