677207307

Appears in sequences

• Sum of divisors of n, sigma(n) (A000203), is a power of number of divisors of n, d(n) (A000005).at n=29A051281
• Numbers k such that sigma(usigma(k)) is prime.at n=7A063103
• Least k such that sigma(k)=m^n for some m>1.at n=29A063869
• Product of first n Mersenne primes = Product_{k=1..n} A000668(k).at n=4A098918
• Smallest number m such that sigma(m) is an n-almost prime.at n=29A152092
• Positions of records in A175432.at n=26A169981
• a(n) is the smallest number N such that sigma(N) is an n-th power but not a higher power, with a(n) = 0 if no such number exists.at n=30A180162
• Numbers k such that sigma(sigma(k)) is prime.at n=6A247838
• a(n) is the smallest number k such that sigma(k) = 2^n or 0 if no such k exists.at n=30A247956
• 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=28A254352
• Least k such that n divides d(sigma(k)) (d = A000005).at n=30A276043
• 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=5A349007
• 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=10A349838