18000

Appears in sequences

• Number of paraffins.at n=17A006009
• arcsinh(sec(x)*tanh(x))=x+20/5!*x^5-280/7!*x^7+18000/9!*x^9...at n=4A012836
• Numbers k that divide the (left) concatenation of all numbers <= k written in base 11 (most significant digit on left).at n=25A029480
• For all n, if d is recursively applied to a(n) exactly 6 times then the fixed point of d-iteration is just reached.at n=25A036458
• Numbers k such that the square of d(k) (number of divisors) divides k.at n=14A046754
• Number of nonempty subsets of {1,2,...,n} in which exactly 2/3 of the elements are <= n/2.at n=18A047162
• Number of nonempty subsets of {1,2,...,n} in which exactly 2/3 of the elements are <= (n-1)/2.at n=18A047173
• Engel expansion of Pi^e = 22.4592.at n=34A059197
• For n>3: a(n) is a multiple of three distinct earlier terms.at n=16A060301
• a(n) is the number of n-digit multiples of n.at n=4A061772
• a(n) is the sum of the divisors of Fibonacci(n) (A000045).at n=21A063477
• Smallest numbers such that the number of terms in inverse set usigma equals n; where usigma = A034448.at n=38A063975
• a(n)=n^2 times nearest cube to n^2.at n=12A077112
• Numbers n such that the digital binary sum of n equals core(n), the squarefree part of n.at n=43A077476
• Numbers n in which the last K digits of n form an integer divisible by K^3, for K = 1, 2, ..., M, where M is the number of digits in n.at n=36A079239
• Numbers n such that n and tau(n) = A000005(n) have the same prime factors (ignoring multiplicity).at n=44A081381
• a(n) = (4*n + 1)*n!.at n=6A082034
• Non-perfect powers k for which q = A051903(k)/A051904(k) is an integer, A051904(k) > 1.at n=2A093770
• Numbers containing squares of Pythagorean triples in their divisor set.at n=4A096472
• a(n)=Product{k=0..n, 1+2^A101650(k)}/2.at n=9A101657