22523

Appears in sequences

• Number of anti-divisors of n (A066272) sets a record.at n=26A073638
• Brilliant numbers k such that 2k+1 is also brilliant.at n=10A085649
• Brilliant numbers (A078972) whose digit reversal is the product of 2 palindromes greater than 1.at n=25A115681
• a(n) = 3 + floor((2 + Sum_{j=1..n-1} a(j))/5).at n=49A120172
• A038610(n) (the LCM of the positive integers that are <= n and are coprime to n) is the a(n)-th positive integer that is coprime to n.at n=15A137450
• a(n) is the largest number k such that there is no pair p+q = 2*k of two non-consecutive primes p < q with p-2*n,p or p,p+2*n consecutive primes and q-2*n,q or q,q+2*n consecutive primes.at n=5A159812
• Numbers n such that Sum(1/d*_n)>Sum(1/d*_m) for all m<n, where d*_n and d*_m are the anti-divisors of n and m.at n=16A192294
• G.f.: Sum_{n>=0} x^n*Product_{k=1..n} (1 - k*x) / (1 - (2*k)*x).at n=8A193321
• Fixed points of permutations A249990 and A252448.at n=14A252458
• Expansion of Product_{k>=1} (1 + x^k)^phi(k), where phi() is the Euler totient function (A000010).at n=26A299069
• a(n) = Sum_{k=1..n} k * tau(k)^2, where tau is A000005.at n=41A320896