405000

Appears in sequences

• a(n) = n*(n-1)^4/2.at n=16A019583
• a(n) = n + (n+1)^2 + (n+2)^3 + (n+3)^4.at n=22A027621
• If there were a unimodular 25-dimensional lattice with minimal norm 3, it would have this as the theta series of its shadow. Unfortunately, no such lattice exists.at n=2A027825
• For n>3: a(n) is a multiple of three distinct earlier terms.at n=34A060301
• a(n) = phi(2^n+1)/(2*n).at n=24A069925
• Smallest order for which there are n nonisomorphic finite Hamiltonian groups, or 0 if no such order exists.at n=26A104453
• Even refactorable numbers k such that the number r of odd divisors and the number s of even divisors are both odd divisors of k and k is the first number for which the triple (r,s,t) occurs, where t is the number of divisors of k.at n=16A120358
• a(n) = ceiling((n+1)^4/2).at n=29A171714
• Number of compositions of odd natural numbers into 4 parts <= n.at n=29A191903
• Number of 2 X 2 matrices with all terms in {0,1,...,n} and even trace.at n=29A210378
• Number of 2 X 2 matrices with all terms in {0,1,...,n} and odd trace.at n=29A210379
• Number of solutions to gcd(x^2 + y^2 + z^2 + t^2 + h^2, n) = 1 with x,y,z,t,h in [0,n-1].at n=14A238533
• Larger of pairs (m, n), such that the difference of their squares is a cube and the difference of their cubes is a square.at n=9A261328
• Numbers k such that k^3 is the sum of two nonzero 4th powers.at n=17A291849
• a(n) = Product_{d|n, d>1} prime(A286622(d)-1).at n=71A305794
• A variant of A322827.at n=39A322825
• a(n) = lcm(n, tau(n), sigma(n), pod(n)) / gcd(n, tau(n), sigma(n), pod(n)) where tau(k) is the number of divisors of k (A000005), sigma(k) is the sum of divisors of k (A000203) and pod(k) is the product of divisors of k (A007955).at n=29A334985
• Least k >= 1 such that sigma(k)/tau(k) has denominator n or zero if no k exists.at n=19A346644
• The smaller of a pair of successive cubefull numbers without a powerful number between them.at n=26A371189
• a(n) = numerator(Integral_{(x,y,z) in R^3 : 0 <= x^2 + y^2 + z^2 <= n^2} (x^2 + y^2) dx dy dz)/Pi.at n=15A387611