3317760

Appears in sequences

• a(n) = phi(2^n - 1)/2.at n=22A056742
• Eighth column of triangle A067417.at n=5A067423
• Products of exactly 18 primes (generalization of semiprimes).at n=27A069279
• a(n+2) = a(n+1)*a(n)*(1+1/n), a(1)=a(2)=1.at n=8A072042
• a(n) = n-th compositorial number / (product of those primes which divide the n-th compositorial number).at n=9A075070
• GCD of sigma(p#) and phi(p#) where p# = A002110(n) is the product of the first n primes.at n=8A078558
• Duplicate of A075070.at n=9A085055
• Sum of the non-unitary divisors of A064115(n) (or of 1+A064115(n)).at n=19A103846
• Numbers that set records for number of ordered factorizations as A025487(j)*A025487(k).at n=28A182763
• A000142 (n+1) * A002109(n), a product of factorials and hyperfactorials.at n=4A240993
• Numerator of new minima of phi(p-1)/(p-1), where phi is Euler's totient function and p = prime(n).at n=19A241197
• Number of double-closed subsets of {1..n}.at n=29A308546
• a(0) = 1; for n > 0, a(n) = (prime(n)^2 - 1) * a(n-1).at n=5A318766
• Denominators in the asymptotic expansion of the Maclaurin coefficients of exp(x/(1-x)).at n=3A321940
• Number of copies of the star graph S(2,1,1) contained within the n-dimensional hypercube graph.at n=9A352847
• a(n) = Product_{d|n} A276086(d)^A349394(n/d).at n=26A380459