81060

Appears in sequences

• a(n) = n*(n+1)*(11*n+1)/6.at n=35A132112
• Numbers n such that phi(n)=d_1!!*d_2!!*...*d_k!! where d_1 d_2 ... d_k is the decimal expansion of n.at n=33A139408
• Triangle T(n,k), n>=0, 0<=k<=n, read by rows: T(n,k) = number of simple graphs on n labeled nodes with k edges where each maximally connected subgraph is either a tree or a cycle.at n=41A144163
• Triangle of sums of the first k n-th powers multiplied by binomial(n,k), read by rows.at n=31A215078
• a(n) = Sum_{k=1..n} binomial(n,k) * sigma_2(k).at n=10A356038