20915

Appears in sequences

• Number of partitions satisfying cn(0,5) + cn(1,5) + cn(4,5) < cn(2,5) + cn(3,5).at n=43A039880
• Numbers whose base-12 representation has exactly 5 runs.at n=21A043654
• Largest proper divisor of the n-th Carmichael number (A002997).at n=13A081703
• The odd composites c such that c=q*g*j*y/2 and q+g=j*y where q,g,j,y are distinct primes.at n=35A167629
• Numbers m having the same sum of divisors as m+20 has.at n=34A181647
• Nonnegative values x of solutions (x, y) to the Diophantine equation x^2+(x+2737)^2 = y^2.at n=40A201916
• For any number n take the polynomial formed by the product of the terms (x-pi), where pi's are the prime factors of n. Then calculate the area between the minimum and the maximum value of the prime factors. This sequence lists the numbers for which the area is equal to zero.at n=41A203614
• Numbers k such that 3^k - 8 is prime.at n=19A217135
• Composite squarefree numbers k such that the arithmetic mean of the distinct prime factors of k is a prime p, and p divides k.at n=33A229094
• Products of three distinct primes that form an arithmetic progression.at n=22A262723
• Numbers x that are equal to lpf(x)*gpf(x)*(lpf(x)+gpf(x))/2, where lpf(x) < gpf(x) are the least and the greatest prime factors of x: A020639 and A006530.at n=25A307108
• Numbers x that are equal to lpf(x)*gpf(x)*(lpf(x)+gpf(x))/2, where lpf(x) and gpf(x) are the least and the greatest prime factors of x: A020639 and A006530.at n=34A307117
• a(n) is the total number of movable letters in all members of the partitions of [n].at n=7A367469