1572861

Appears in sequences

• Divisors of 2^38 - 1.at n=5A003544
• Numbers that are a product of distinct Mersenne primes (elements of A000668).at n=27A046528
• New record highs reached in A060030.at n=38A060482
• Least k such that sigma(k)=m^n for some m>1.at n=20A063869
• A multiplicative version of 2^n - 1 (A000225).at n=37A064084
• Numbers n such that sigma(n) is a prime power (A025475).at n=28A065523
• G.f.: (x+2)*(x+1)/((x-1)*(x-2)) = Sum_{n>=0} a(n)*(x/2)^n.at n=19A068156
• Least k such that A072084(k) = n.at n=37A072087
• a(n) = a(n-1) + 2*a(n-2) - 2*a(n-3).at n=37A136252
• Semiprimes that are a product of Mersenne primes.at n=16A144482
• Semiprimes that are a product of distinct Mersenne primes.at n=12A144856
• Numbers whose binary representation is a palindrome formed from the reflected decimal expansion of the concatenation of 1, 0 and infinite digits 1.at n=20A147758
• Number of reduced words of length n in Coxeter group on 3 generators S_i with relations (S_i)^2 = (S_i S_j)^20 = I.at n=20A168824
• Positions of records in A175432.at n=17A169981
• 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=21A180162
• Expansion of x*(3*x^2+x+1)/((x-1)*(2*x-1)*(x+1)).at n=20A192033
• a(n) is the smallest number k such that sigma(k) = 2^n or 0 if no such k exists.at n=21A247956
• Product of lowest and highest prime factors of 2^n-1.at n=36A249780
• Nonprime numbers k such that sum of the divisors of k is a power of 2.at n=20A254603
• Numbers whose arithmetic derivative is equal to their BCR, where BCR = A036044, binary-complement-and-reverse = take one's complement then reverse bit order.at n=16A269633