26809

Appears in sequences

• Number of positive integers <= 10^n that are divisible by no prime exceeding 17.at n=8A108275
• Number of n X n binary arrays symmetric about both diagonal and antidiagonal with all ones connected only in a 1111-1111 pattern in any orientation.at n=19A146937
• Numbers n such that 10^n+2*n+1 is prime.at n=13A174178
• Least number k > n such that n concatenated with k produces a cube.at n=47A243092
• Least number k such that n concatenated with k produces a cube.at n=47A245631
• A(n,k) is the sum over all Motzkin paths of length n of products over all peaks p of (x_p+k*y_p)/y_p, where x_p and y_p are the coordinates of peak p; square array A(n,k), n>=0, k>=0, read by antidiagonals.at n=65A258306
• T(n,k) = 1/k! * Sum_{i=0..k} (-1)^(k-i) *C(k,i) * A258306(n,i); triangle T(n,k), n>=0, 0<=k<=floor(n/2), read by rows.at n=30A258307
• Sum over all Motzkin paths of length n of products over all peaks p of x_p/y_p, where x_p and y_p are the coordinates of peak p.at n=10A258312
• Number of Dyck paths of semilength n such that the number of peaks is weakly decreasing from lower to higher levels.at n=13A288140
• Numbers k for which rank of the elliptic curve y^2=x^3+k*x is 4.at n=24A309031
• a(n) is the Wiener index of a broom on 2n vertices of which n+2 are pendant.at n=31A349416