544635

Appears in sequences

• Number of polyominoes with n cells that tile the plane isohedrally.at n=15A075205
• Numbers k for which sigma(k)/k - 2/7 is an integer.at n=3A218409
• Terms of A050973 that give maximum record values for A050973(k)/A050972(k).at n=7A236355
• Numbers n such that rad(sigma(n)) = 2*rad(n), where the "radical" of n, rad(n), is A007947 and sigma(n) is the sum of the divisors of n.at n=4A238330
• Odd integers k such that sigma(k)^2 is divisible by k.at n=5A263983
• Numbers n such that the set of prime divisors of n is equal to the set of prime divisors of sum of proper divisors of n while n is not in A027598.at n=29A286876
• Odd numbers k such that the set of distinct prime divisors of k is equal to the set of distinct prime divisors of the sum of proper divisors of k.at n=2A286884
• The odd part of those numbers which divide the sum of their divisors (A007691).at n=10A320024
• Numbers k such that the squarefree kernel of sigma(k) is equal to the squarefree kernel of 2*k.at n=38A332208
• Odd numbers k such that rad(k) divides sigma(k).at n=29A336554
• Numbers k for which sigma(k)/k = 16/7.at n=3A347169
• Odd numbers k for which A000005(k) >= A017665(k), where A000005 is the number of divisors function, and A017665 is the numerator of the abundancy ratio, sigma(k)/k.at n=1A388269
• Odd numbers k for which A000005(2*k) >= A017665(2*k), where A000005 is the number of divisors function, and A017665 is the numerator of the abundancy ratio, sigma(k)/k.at n=14A388277