18240
domain: N
Appears in sequences
- Representation degeneracies for boson strings.at n=32A005293
- Numbers k such that the least term in the periodic part of the continued fraction for sqrt(k) is 18.at n=14A031696
- Number of partitions in parts not of the form 23k, 23k+1 or 23k-1. Also number of partitions with no part of size 1 and differences between parts at distance 10 are greater than 1.at n=46A035989
- Numbers k such that k^3 has only even digits.at n=17A052004
- a(n) = n*(n+2)*(n-2)/3.at n=36A077415
- Least common multiple of prime(n+1)-1 and prime(n)-1.at n=42A083554
- a(0) = 1, a(n) = 480*sigma(n).at n=37A083728
- a(n) = T(n)^2 - n^2, where T(n) is a triangular number.at n=16A085740
- Number of points of self-intersection of the path of a billiard ball traveling at a 45-degree angle on a prime(n) X prime(n+1) billiard table. Also equal to 1/2 the number of the lattice points lying within a prime(n) X prime(n+1) rectangle.at n=42A099407
- Number of ways to change three non-identical letters in the word aabbccdd..., where there are n types of letters.at n=18A102860
- a(1)=1, a(n) = first index i (> a(n-1)), where A112046(i) gets a value distinct from any values A112046(1)..A112046(a(n-1)).at n=42A112051
- 12 times pentagonal numbers: a(n) = 6*n*(3*n-1).at n=32A153792
- a(n) = 225*n^2 + 15.at n=9A158557
- Triangle T(n,k) = Number of k-cycles on the graph of an n-orthoplex. n>=2, k>=3.at n=16A167986
- Numbers with prime factorization pqrs^6.at n=6A190292
- Level of the n-th plateau of the column k of the square array A195825, when k -> infinity.at n=12A210843
- a(n) = (prime(n)^2 - 1)/2 for n >= 2.at n=41A216244
- Triangle read by rows: T(n,k), n>=1, k>=1, in which column k lists the numbers of A210843 multiplied by A000330(k), and the first element of column k is in row A000217(k).at n=32A249120
- Number of elements of S_n with strategic pile of size 5.at n=8A267391
- Irregular triangle read by rows T(n,m), coefficients in power/Fourier series expansion of an arbitrary anharmonic oscillator's exact phase space angular velocity.at n=54A276814