45864

Appears in sequences

• Jordan function J_n(6) (see A059379).at n=6A059387
• Numbers m such that the sum of the first k divisors of m is equal to m for some k.at n=9A064510
• J_n(n), where J is the Jordan function, J_n(n) = n^n product{p|n}(1 - 1/p^n), the product is over the distinct primes, p, dividing n.at n=5A067858
• Jordan function J_6(n).at n=5A069091
• Smallest k such that k and k+n have the same prime signature that is different from all previous terms.at n=35A085876
• Ooguri-Vafa invariants of disk degeneracies for brane III in the O(K) -> P^1 x P^1 geometry.at n=9A092719
• Ooguri-Vafa invariants of disk degeneracies for brane III in the O(K) -> P^1 x P^1 geometry.at n=7A092721
• A B3-sequence: a(1) = 1; for n>1, a(n) = smallest number > a(n-1) such that the sums of any three terms are all distinct.at n=27A096772
• a(n) = gcd(n!, binomial(2n,n)).at n=25A135322
• Coefficients of derivatives of MacMahon polynomials (A060187): p(x,n)=2^n*(1 - x)^(1 + n)*LerchPhi[x, -n, 1/2]; p'(x,n)=(d/dx)p{x,n).at n=34A142707
• Number of n X n symmetric 0..7 arrays with rows, considered as 8-ary numbers, in strictly increasing order.at n=2A162132
• a(n) = C(2n,n) * (7^n/n!^2) * Product_{k=0..n-1} (7k+1)*(7k+6).at n=2A184896
• Numbers with prime factorization p*q^2*r^2*s^3 (where p, q, r, s are distinct primes).at n=15A190109
• Erdős-Nicolas numbers.at n=4A194472
• Numbers whose square is the product of a number and its reverse.at n=19A207373
• Numbers n with the property that, if tau(n) = k = number of divisors of n, and the d(i) are the divisors [arranged in increasing order], then the sum 1/d(k) + 1/d(k-1) + 1/d(k-2) + ... + 1/d(q) is an integer for some q.at n=16A226476
• Nonsquare numbers whose sum of proper square divisors is a square greater than 1.at n=15A232555
• Numbers whose sum of proper square divisors is a square greater than 1.at n=18A232556
• Numbers k such that k^2 +- k +- 1 is prime for all four possibilities.at n=13A236056
• Product_{i=1..n} J_6(i) where J_6(i) = A069091(i).at n=2A239672