56048

Appears in sequences

• Combinatorial prime formulas. This sequence gives the coefficients a(n) of combinatorial sum formulas of n-th primes or lesser: prime(n) = 2^(n-5)/(n-1)! Sum_{i=1..n} a(i) * C(n-1,i-1) * (1-(n-i)/2).at n=8A120315
• Numbers d*p where d is a perfect number and p<d a prime not dividing d.at n=37A165772
• Number of n-node unlabeled rooted trees with thickening limbs and root outdegree (branching factor) 5.at n=43A245145
• Number of terms in the cycle index Z(S_n X S_n) of the Cartesian product of the symmetric group S_n with itself that contain q cycles, where 1 <= q <= n*n. (Triangular array.)at n=66A279514
• Numbers k such that A070313(k) = 2^k - (2*k+1) is a prime number.at n=15A344781
• Numbers k such that k divides A243071(k).at n=38A364497
• Irregular triangular array read by rows. Let S_n be the set of labeled graphs G on [n] with 2-colored nodes where black nodes are only connected to white nodes and vice versa. Orient the edges in each such graph G from black to white. T(n,k) is the number of graphs in S_n containing exactly k descents, n>=0, 0<=k<=A002620(n).at n=52A381058