27559

Appears in sequences

• Numbers whose sum of divisors is a fifth power.at n=24A019423
• Numbers k such that phi(k) is equal to A008473(k+1).at n=10A039781
• Numbers that are a product of distinct Mersenne primes (elements of A000668).at n=16A046528
• Zeisel numbers.at n=9A051015
• Sum of divisors of n, sigma(n) (A000203), is a power of number of divisors of n, d(n) (A000005).at n=10A051281
• Numbers n such that sigma(n) is a prime power (A025475).at n=17A065523
• Numbers n such that sigma(n) is a power of prime (of the form p^a, p prime, a>=1).at n=34A070763
• (L)-sieve transform of A004767 = {3,7,11,15,...,4n-1,...}.at n=32A155167
• a(n) is the least composite x such that sigma(x) divides (x-1)^n but not (x-1)^(n-1), for n >= 2.at n=13A254352
• Nonprime numbers k such that sum of the divisors of k is a power of 2.at n=11A254603
• Composite numbers k such that sum of proper divisors of k divides 2^k-1.at n=8A278315
• Alternating sum of row 2n of A022166.at n=4A290974
• a(n) is the largest number k such that sigma(k) = 2^n or 0 if no such k exists.at n=15A295043
• Sphenic numbers that are the product of Mersenne primes.at n=3A346138
• a(1) = 1; for n > 1, a(n) is the largest number m such that sigma(m) = tau(m)^n or 0 if no such m exists.at n=4A349007
• Irregular table read by rows; the n-th row contains in ascending order the integers m > 1 such that sigma(m) = tau(m)^n; the first row contains 1.at n=7A349838