18107

Appears in sequences

• a(n) = (1/1 - 1/2 + ... + (-1)^(n-1)/n)*lcm{1..n}.at n=11A025530
• Numerator of the n-th alternating harmonic number, Sum_{k=1..n} (-1)^(k+1)/k.at n=11A058313
• Numbers k such that k*2^m+1 are composites for all exponents m in the range 0<=m<=k.at n=34A061153
• Last number of height n in Recamán's sequence A005132.at n=26A064293
• Let u(1) = x and u(n+1) = (n^2/u(n)) + 1 for n >= 1; then a(n) is such that u(n) = (b(n)*x + c(n))/(a(n)*x + d(n)) (in lowest terms) and a(n), b(n), c(n), d(n) are positive integers.at n=12A075830
• Numerator of Sum_{k=1..n} 1/(n+k).at n=5A082687
• Numerator of the fraction n*Sum_{k=1..n} 1/(n+k).at n=5A117731
• Numerator of the product of n and the n-th alternating harmonic number, Sum_{k=1..n} (-1)^(k+1)/k.at n=11A119787
• Absolute value of numerator 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=11A120301
• Numerator of h(n+6) - h(n), where h(n) = Sum_{k=1..n} 1/k.at n=6A192359
• G.f. satisfies: A(x) = Sum{n>=0} A( n*x/(1-n*x) ) * x^n, with A(0)=1.at n=7A227222
• Number of vertices in regular n-gon after 2 generations of mitosis.at n=19A349967
• Number of integer partitions of n that can be partitioned into sets with distinct sums.at n=39A381992