18360

Appears in sequences

• Theta series of direct sum of 3 copies of hexagonal lattice.at n=26A008654
• Weight distribution of [ 18,9,8 ] self-dual code over GF(4).at n=5A014487
• Theta series of A_17 lattice.at n=2A023908
• a(n) = n*(n+1)*(n+2)*(n+3)/4.at n=15A033487
• Numerators of continued fraction convergents to sqrt(573).at n=5A042098
• Triangle of numbers related to rooted trees and unrooted planar trees.at n=18A056856
• McKay-Thompson series of class 38A for Monster.at n=48A058657
• a(n) = binomial(2*n, n) mod ((n+1)*(n+2)*(n+3)*(n+4)).at n=13A065346
• Number of functions from [1,2,...,n] to [1,2,...,n] such that the image contains exactly two elements.at n=7A068605
• First differences of A069475, successive differences of (n+1)^6-n^6.at n=23A069476
• Numbers k not in A065036 but such that tau(k) = omega(k)^3.at n=15A074853
• Number of 3 X n (0,1) matrices such that each row and each column is nondecreasing or nonincreasing.at n=19A086113
• A generalization of triangle A071951 (Legendre-Stirling).at n=11A089504
• Second column of triangle A089504 and second column of array A078741 divided by 18.at n=3A089507
• Numbers k such that sigma(k) divides k^2.at n=19A090777
• Triangle of scaled second column sequences of (k,k)-Stirling2 arrays.at n=17A091039
• Triangle read by rows: T(n,h) = number of functions f:{1,2,...,n}->{1,2,...,n} such that |Image(f)|=h; h=1,2,...,n, n=1,2,3,... . Essentially A090657, but without zeros.at n=37A101817
• a(n) = 4*n*(4*n - 1).at n=34A104188
• Triangle read by rows, related to A108283.at n=26A108284
• Numbers with at least two 3s in their prime signature.at n=44A109399