81690

Appears in sequences

• Triangle T(n,k) of series-reduced (or homeomorphically irreducible) labeled graphs with n nodes and k edges, k=0..binomial(n,2).at n=55A060514
• Numbers k having exactly 5 distinct prime factors, the largest of which is greater than or equal to sqrt(k) (i.e., sqrt(k)-rough numbers with exactly 5 distinct prime factors).at n=30A115959
• a(n) = [x^n] (1 + x*(1+x)^(n+1) )^(n+1).at n=6A121680
• A binomial conjugate of the Narayana numbers.at n=59A177896
• Array: row n shows the coefficients of the characteristic polynomial of the n-th principal submatrix of the symmetric matrix A203003; by antidiagonals.at n=22A203004
• Number T(n,k) of sets of exactly k nonempty words with a total of n letters over n-ary alphabet such that within each prefix of a word every letter of the alphabet is at least as frequent as the subsequent alphabet letter; triangle T(n,k), n>=0, read by rows.at n=46A293815
• Number of sets of exactly two nonempty words with a total of n letters over n-ary alphabet such that within each prefix of a word every letter of the alphabet is at least as frequent as the subsequent alphabet letter.at n=9A293964