238080
domain: N
Appears in sequences
- Differences between factorials and Xfactorials: A048631 - A000142.at n=9A048632
- a(n) = ((2^b-1)/phi(n))*Sum_{d|n} Moebius(n/d)*d^(b-1) for b = 5.at n=15A160894
- n such that n = product of 3 consecutive even numbers and n+-1 are primes.at n=6A174384
- Triangle read by rows: T(n, k) is the smallest x such that the denominator of sigma(x)/x is equal to n and the numerator of sigma(x)/x is congruent to k modulo n.at n=38A242370
- a(n) = Sum_{-n<i<n, -n<j<n, gcd{i,j}=1} (n-|i|)*(n-|j|).at n=24A331771
- Numbers k such that the continued fraction of the abundancy index of k contains a single distinct element.at n=21A349686
- Product_{n>=1} (1 + a(n)*x^n/n!) = 1 + arctan(x).at n=9A353820