840840

Appears in sequences

• a(n) = n!/(1!*2!*3!*...*k!) where k is the largest integer such that 1!*2!*3!*...*k! divides n!.at n=15A074199
• Numbers that can be expressed as the difference of the squares of primes in exactly sixteen distinct ways.at n=6A092012
• a(n) = (A093886(n))! / (1!*2!*3!*...*n!).at n=5A093887
• Denominator of Sum_{k=1..n} H(k)*H(n+1-k), where H(k) is the k-th harmonic number (Sum_{j=1..k} 1/j).at n=12A130895
• Triangle of unsigned 4-Lah numbers.at n=31A143499
• Numbers with exactly 6 distinct prime divisors {2,3,5,7,11,13}.at n=24A147573
• Numbers with prime factorization pqrst^2u^3.at n=15A190390
• Average of twin prime pairs n having their decimal expansion of the form abcabc or abcabc0 such that n contains three twin primes as divisors.at n=8A235716
• Number of obtuse isosceles triangles on a centered hexagonal grid of size n.at n=18A241230
• Maximum number of binary strings of length 2n obtained from a partition of n.at n=13A247651
• Number T(n,k) of length 2n k-ary words, either empty or beginning with the first letter of the alphabet and using each letter at least once, that can be built by repeatedly inserting doublets into the initially empty word; triangle T(n,k), n>=0, 0<=k<=n, read by rows.at n=34A256116