617610

Appears in sequences

• Number of nonempty subsets of {1,2,...,n} in which exactly 2/5 of the elements are <= (n-1)/3.at n=23A048011
• Number of nonempty subsets of {1,2,...,n} in which exactly 2/5 of the elements are <= (n-2)/3.at n=23A048022
• Number of nonempty subsets of {1,2,...,n} in which exactly 2/5 of the elements are <= (n-3)/3.at n=23A048033
• Triangle T(n,k) read by rows: the number of n X n {0,1} matrices with trace k where each row sum and each column sum is 2.at n=31A284989
• Sequence gives the denominators, in increasing values, of Egyptian fractions such that their sum has the concatenation of these denominators as decimal part. Case a(1) = 10.at n=2A302933
• Sequence gives the denominators, in increasing values, of Egyptian fractions whose sum has the concatenation of these denominators as decimal part. Case a(1) = 4.at n=3A304286
• Number of vertices in an equilateral triangle "frame" of size n (see Comments in A328526 for definition).at n=35A333031