151263

Appears in sequences

• Numbers of form 7^i*9^j, with i, j >= 0.at n=22A025631
• Numbers whose prime factors are 3 and 7.at n=25A033850
• Numbers that can be written as k/d(k) in four or more ways, where d(k) = number of divisors of k.at n=15A051346
• Numbers that factorize into a prime number of factors all raised to different prime exponents and no number appears both as an exponent and as a prime factor.at n=32A114131
• Numbers such that each of the first 2j primes appears exactly once in the prime factorization, either as factor or exponent.at n=11A114132
• Numbers k such that previous_prime(k)=k-sd and next_prime(k)=k+sd where sd is sum of the distinct prime factors of k.at n=12A125841
• Product of the 5th power of a prime and different distinct prime of the 2nd power (p^5*q^2).at n=29A179646
• a(n) = 7*(a(n-1) - a(n-2) - a(n-3)), with a(0)=3, a(1)=7, a(2)=35.at n=7A215575
• Numbers n such that n = k/d(k) has exactly 4 solutions, where d(k) = number of divisors of k.at n=13A217125
• Numbers k = p1^e1*p2^e2, with e1 != e2, such that the Euclidean distance between points (p1, e1) and (p2, e2) is an integer.at n=14A387172
• a(n) is the conjectured largest number such that both a(n) and a(n) - n are 11-smooth numbers, or 0 if no such number exists. a(n) can be less than n.at n=12A392256