870870

Appears in sequences

• Triangle read by rows in which row n contains first n numbers with exactly n distinct prime factors.at n=25A048692
• Smallest number beginning with 8 and having exactly n distinct prime divisors.at n=6A077333
• Smallest number with n prime divisors such that the sum of the prime divisors is also a divisor, or 0 if no such number exists.at n=6A086487
• Partial products of A102926.at n=6A102927
• a(n) is the least k with n distinct prime factors such that the sum of its prime factors (counting multiplicity) divides k, or 0 if no such k exists. First member of A036844 with n distinct prime factors.at n=6A104466
• Smallest number beginning with 8 that is the product of exactly n distinct primes.at n=6A106418
• Products of 7 distinct primes (squarefree 7-almost primes).at n=4A123321
• Numbers that are divisible by exactly 7 distinct primes.at n=4A176655
• Partitions of n labeled elements into subsets of two or three elements.at n=13A227937
• Numbers n such that n = concatenate(a, b) and sigma(a) + sigma(b) = phi(n).at n=28A249065
• Numbers other than prime powers divisible by the sum and the sum of squares of their prime divisors.at n=28A268417
• Irregular triangle read by rows: T(m, k) is the list of squarefree numbers A002110(m) < t < 2*A002110(m) such that A001221(t) = m.at n=17A288813
• Totient superdeficient numbers: numbers n > 1 such that s(n)/n < s(m)/m for all m < n, where s(n) is the sum of iterated phi(n) (A092693).at n=16A291173
• Least squarefree number with n prime factors whose average is an integer.at n=6A300393
• Numbers k with a record number of divisors d < sqrt(k) such that d + k/d is prime.at n=15A331665
• Composite squarefree numbers k = Product_{i} p_i such that k^2 is divisible by Sum_{i} p_i^2.at n=19A332738
• a(n) is the least k such that there are exactly n divisors d of k for which k/d-d is prime.at n=42A340729