20618

Appears in sequences

• Numbers k such that k*Sum_{d|k} 1/sigma(d) is an integer.at n=20A069166
• Group successively larger prime numbers so that the sum of the n-th group is a multiple of n. Sequence gives the group sum divided by n for the n-th group.at n=40A074131
• a(n) = A077704(n+1)/A077704(n).at n=13A077705
• Number of distinct products i*j*k*l for 1 <= i <= j <= k <= l <= n.at n=38A100437
• Number of different cuboids with volume (pq)^n, where p,q are distinct prime numbers.at n=25A101427
• Maximum value of the n-th difference of a permutation of 0..n.at n=12A130783
• Zero followed by partial sums of A059100, starting at n=1.at n=39A145068
• Partial sums of A160120.at n=44A162778
• Number of binary strings of length n with equal numbers of 0010 and 0110 substrings.at n=16A164168
• a(n) = Sum_{k=0..floor(n/2)} k*binomial(n,k).at n=13A185251
• Second elementary symmetric function of the first n terms of (2,2,3,3,4,4,5,5...).at n=24A203299
• a(n) = Sum_{k = 0..n} k*binomial(2*n+1, k).at n=6A303602