4084080

Appears in sequences

• a(n) = denominator of harmonic number H(n) = Sum_{i=1..n} 1/i.at n=17A002805
• Numbers k such that sigma(k)/phi(k) sets a new record.at n=32A018894
• Denominator of n * n-th harmonic number.at n=18A027611
• a(n) = n^5 - n.at n=21A061167
• Denominator of Sum_{k=1..n} d(k)/k, where d() = A000005().at n=16A065080
• Denominator of Sum_{k=1..n} d(k)/k, where d() = A000005().at n=17A065080
• a(n) is the least common multiple of numbers in {1,2,3,...,n-1} which do not divide n.at n=17A067391
• Denominator of Sum_{1<=k<=n, gcd(k,n)=1} 1/k.at n=18A069220
• Denominators of a(n+1) = Sum_{k=1..n} a'(n/k), a(1)=1, where a'(x)=a(x) if x integer and is linearly interpolated otherwise.at n=35A071796
• Denominators of harmonic numbers when the numerators are divisible by squares of primes >= 5 in the case of Wolstenholme's Theorem.at n=5A076638
• LCM of the terms of the n-th row of the triangle pertaining to A083130.at n=6A083135
• Max{ k!/(a(1)!*a(2)!*..*a(n)!) : a(1) + 2*a(2) + 3*a(3) + ... + n*a(n) = n, a(1) + a(2) + ... + a(n) = k }.at n=29A102462
• a(n) = (6*n)!/((3*n)!*(2*n)!*n!).at n=3A113424
• Denominator of 1^n/n + 2^n/(n-1) + 3^n/(n-2) + ... + (n-1)^n/2 + n^n/1.at n=17A120487
• Smallest positive number of "triangular" shuffles of n(n+1)/2 cards needed to restore them to their original order.at n=16A122158
• Where records occur in A018892.at n=37A126098
• a(n) = denominator of sum{k=1 to n} 1/A127518(k).at n=17A127520
• a(n) = floor((denominator of H(n))/n), where H(n) = Sum_{k=1..n} 1/k, the n-th harmonic number.at n=18A128438
• Increasing sequence obtained by union of two sequences A136354 and {b(n)}, where b(n) is the smallest composite number m such that m+1 is prime and the set of distinct prime factors of m consists of the first n primes.at n=12A136357
• Increasing sequence obtained by union of two sequences {b(n)} and {c(n)}, where b(n) is the smallest odd composite number m such that both m-2 and m+2 are prime and the set of distinct prime factors of m consists of the first n odd primes and c(n) is the smallest composite number m such that both m-1 and m+1 are primes and the set of the distinct prime factors of m consists of the first n primes.at n=12A136358