57337

Appears in sequences

• Divisors of 2^39 - 1.at n=5A003545
• Numbers that are a product of distinct Mersenne primes (elements of A000668).at n=17A046528
• Integers whose sum of divisors is an 8th power.at n=2A048258
• a(n) = T(8,n), array T given by A047858.at n=12A048469
• Sum of divisors of n, sigma(n) (A000203), is a power of number of divisors of n, d(n) (A000005).at n=11A051281
• Numbers k such that sigma(usigma(k)) is prime.at n=4A063103
• Numbers k such that usigma(sigma(k)) is prime.at n=2A063836
• Least k such that sigma(k)=m^n for some m>1.at n=15A063869
• A multiplicative version of 2^n - 1 (A000225).at n=38A064084
• Numbers n such that sigma(n) is a prime power (A025475).at n=18A065523
• Numbers n such that sigma(n) is a power of prime (of the form p^a, p prime, a>=1).at n=38A070763
• Least k such that A072084(k) = n.at n=38A072087
• Numbers k such that 2^(k(k-1)) == 8 (mod k).at n=7A126662
• Semiprimes that are a product of Mersenne primes.at n=11A144482
• Semiprimes that are a product of distinct Mersenne primes.at n=7A144856
• Partial sums of A162396.at n=25A164120
• Positions of records in A175432.at n=12A169981
• 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=16A180162
• L.g.f.: Sum_{n>=1} a(n)*x^n/n = Sum_{n>=1} x^n/n * exp( Sum_{k>=1} a(k)*x^(n*k)/k ).at n=11A209397
• Number of idempotent n X n 0..3 matrices of rank n-1.at n=6A224328