62160

Appears in sequences

• Numbers n such that phi(sigma(n)) = 5*phi(n).at n=12A067708
• Matrix product of Stirling2-triangle A008277(n,k) and unsigned Stirling1-triangle |A008275(n,k)|.at n=31A079641
• Even numbers k such that the central binomial coefficient A000984(k, k/2) is divisible by k^2.at n=32A080395
• Ordered m for which m = k^3*a*b*(a^4 - b^4) determine (unique) solution triples(k,a,b), where k=1,2,3,... and (a,b) are coprime pairs, not both odd (i.e., of opposite parity).at n=33A081779
• Numbers that can be expressed as the difference of the squares of primes in exactly nine distinct ways.at n=6A092005
• T(n, k) = [x^k] Sum_{k=0..n} Stirling2(n, k)*RisingFactorial(x, k), triangle read by rows, for n >= 0 and 0 <= k <= n.at n=40A129062
• If X_1, ..., X_n is a partition of a 2n-set X into 2-blocks then a(n) is equal to the number of 3-subsets of X containing none of X_i, (i=1,...,n).at n=34A130809
• Numbers with prime factorization p*q*r*s*t^4 (where p, q, r, s, t are distinct primes).at n=14A190110
• Number of symmetry classes of 3-eared triangulations of an n-gon.at n=13A232492
• Product of n and the sum of all divisors of all positive integers <= n.at n=41A256533
• a(n) is the number of partitions of the set {1,2,...,n} into lists having a prime number of elements.at n=8A351940
• E.g.f. satisfies A(x) = 1/(1 - x)^(x^2 * A(x)).at n=8A355287