195300

Appears in sequences

• a(n) = n*(n^3 - 1)/2.at n=23A027482
• Number of primitive (aperiodic) reversible strings with n beads using a maximum of five different colors.at n=7A056316
• Numbers k such that sigma(k) - usigma(k) is a square and sets a new record for such squares.at n=35A063840
• Numbers k such that (1/k) * Sum_{d|k} d*sigma(d) is an integer.at n=27A069520
• Numbers with prime factorization pqr^2s^2t^2.at n=16A190379
• Sequence of coefficients of x^1 in marked mesh pattern generating function Q_{n,132}^(0,4,0,0)(x).at n=29A212347
• Triangle read by rows: T(n,k) is the number of subpermutations of an n-set, whose orbits are each of size at most k with at least one orbit of size exactly k, and without fixed points. Equivalently, T(n,k) is the number of partial derangements of an n-set each of whose orbits is of size at most k with at least one orbit of size exactly k, and without fixed points.at n=40A261765
• Triangle read by rows: T(n, k) = Sum_{t=k..n-3} (-1)^(t-k)*(n-t)!*binomial(t,k)*binomial(n-3,t).at n=40A264028
• Numbers k for which sigma(k)/k = 832/225.at n=1A348021
• Triangle read by rows. The incomplete Bell transform of the central binomial numbers.at n=50A352369
• Numbers k such that k +- 2 and k +- 3 are all semiprimes.at n=41A382049