3243240

Appears in sequences

• Numbers that can be expressed as the difference of the squares of primes in exactly sixteen distinct ways.at n=18A092012
• a(n) is the smallest number x such that floor(sigma(sigma(x))/x) = n or the A098219(x) quotient equals n.at n=19A098221
• Where records occur in A144262.at n=13A144376
• Triangle T(n,k) read by rows: number of k-lists (ordered k-sets) of disjoint 2-subsets of an n-set, n>1, 0<k<=floor(n/2).at n=39A157018
• Number of permutations sigma of [n] without fixed points such that sigma^10 = Id.at n=13A261381
• Highly composite numbers of class 3 (see comment in A275239).at n=35A275241
• Triangle read by rows: T(n,k) = (4*n - 3*k)!/((n-k)!^4*k!).at n=33A318105
• a(n) is the least integer k such that sigma(sigma(k)) >= n*k where sigma is A000203, the sum of divisors.at n=19A327630