21162960

Appears in sequences

• a(n) = (1/C(2n,0) - 1/C(2n,1) + ... + d/C(2n,2n))*L, where d = (-1)^2n, L = LCM{C(2n,0), C(2n,1),..., C(2n,2n)}.at n=10A025535
• a(n) = 28*(n+1)*binomial(n+3,8)/3.at n=12A027793
• a(n) = 91*(n+1)*binomial(n+3,14)/3.at n=6A027799
• a(n) is the smallest number which has n consecutive divisors k, k+1, ..., k+n-1 such that the quotients all begin with the same digit.at n=8A053014
• a(n) is the smallest number which has n consecutive divisors k, k+1, ..., k+n-1 such that the quotients all begin with the same digit.at n=9A053014
• a(n) is the least common multiple of numbers in {1,2,3,...,n-1} which do not divide n.at n=21A067391
• 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=44A071796
• Denominator of n*sum(k=1,(-1)^(k+1)/(n+k)).at n=10A082690
• Smallest number not yet used that is either a divisor or multiple of both n and a(n-1).at n=18A119862
• Smallest number divisible by all numbers from 1 to 2*n-1, but not divisible by n, or 0 if impossible.at n=9A230478
• Denominator of n*Sum_{k=1..n} 1/(n+k).at n=10A296519
• a(n) is the period of the periodic k-sequence q_k=lcm(k+1,k+2,...,k+n)/(n*binomial(k+n,n)).at n=21A319404
• Smallest number whose divisors > 1 have a longest run of length n, and 0 if none exists.at n=9A328448
• Denominator of the sum of all elements of the n X n matrix M with M[i,j] = (-1)^(i+j)*i/j for i,j = 1..n.at n=20A334724
• Denominator of the sum of all elements of the n X n matrix M with M[i,j] = (-1)^(i+j)*i/j for i,j = 1..n.at n=21A334724
• Denominator of Sum_{1<=j<=k<=n, gcd(j,k)=1} 1/(j*k).at n=20A365228