31269

Appears in sequences

• sigma(n) + phi(n) is a fourth power.at n=9A114068
• an=n-th smallest integer m=p1*p2*p3, product of 3 odd primes such that d+2m/d are all primes for d dividing 2m.at n=20A128278
• Triangle of coefficients of polynomials v(n,x) jointly generated with A209773; see the Formula section.at n=51A209774
• Numbers n such that sigma(n) + phi(n) is a composite number of the form p^k where p is a prime.at n=10A230770
• Number of partitions p = [x(1), ..., x(k)], where x(1) >= x(2) >= ... >= x(k), of n such that max(x(i) - x(i-1)) is a part of p.at n=45A241735
• Expansion of (-1 + Product_{k>=1} 1 / (1 - x^k))^7.at n=6A341226
• G.f. A(x) satisfies: [x^n] A(x)^(n+1) = [x^n] (1 + x*A(x)^(2*n+1))^(n+1) for n >= 0.at n=5A360345
• Numbers k such that k + sopfr(k) is a cube.at n=25A389862
• a(n) is the least k such that k + sopfr(k) has exactly n prime factors, counted with multiplicity.at n=15A389973