42840

Appears in sequences

• a(n) = n*(n-1)*(n-2) (or n!/(n-3)!).at n=36A007531
• Number of ways for n-3 nonintersecting loops to cross a line 2n times.at n=3A007746
• Theta series of D_6 lattice.at n=26A008428
• Triangle read by rows: T(n,k) = number of closed meander systems of order n with k<=n components.at n=24A008828
• Number of labeled polygonal cacti (Husimi graphs) with n nodes.at n=8A035088
• Number of 2n-bead balanced binary strings, rotationally inequivalent to reverse, complement and reversed complement.at n=9A045657
• Number of 2n-bead balanced binary strings of fundamental period 2n, rotationally inequivalent to reverse, complement and reversed complement.at n=9A045666
• Triangle of numbers related to triangle A049375; generalization of Stirling numbers of second kind A008277, Lah-numbers A008297...at n=17A049385
• Number of labeled pure 2-complexes on n nodes (0-simplexes) with 4 2-simplexes and 12 1-simplexes.at n=2A054647
• a(n) = 3*n*(3*n-1)*(3*n-2).at n=12A054776
• a(n) = lcm(6n+2, 6n+4, 6n+6).at n=11A061506
• Denominator of sum of first n terms of the series 1/15 + 1/63 + 1/80 ... in which the denominators are perfect squares - 1 which are simultaneously other powers, e.g. a(1) = 15 because 16 = 4^2 = 2^4, a perfect square that is also a fourth power; hence 16-1 = 15 qualifies as a term.at n=5A062757
• Numbers expressible as (a^2-1)(b^2-1) in at least 2 distinct ways (b>=a>1).at n=26A063067
• Index values for new maxima in sequence A007365.at n=33A065932
• Numbers n such that sigma(n)^2 > 9*sigma_2(n) where sigma_2(n) is the sum of squares over the divisors of n.at n=21A068378
• Numbers k such that phi(k) = tau(k)^2.at n=31A068560
• a(n) = (2*n+2)*(2*n+3)*(2*n+4) = 24*A000330(n+1).at n=16A069074
• Denominators of expansion of 1/x+1/log(1-x).at n=33A075178
• Square roots of products of members of groups in A076031.at n=5A076030
• Number of conjugacy classes in the group GL(3,Z_n).at n=35A086768