20055

Appears in sequences

• Odd numbers with exactly 4 distinct palindromic prime factors.at n=6A046406
• Sums of terms of groups in A075626.at n=34A075629
• Numbers k such that 2k+1, 4k+1, 6k+1 and 8k+1 are primes.at n=14A124409
• Numbers k such that k and k^2 use only the digits 0, 2, 3, 4 and 5.at n=37A136882
• G.f. satisfies: A(x) = Sum_{n>=0} x^n * Product_{d|n} A(x^d)^(n/d).at n=10A206302
• Triangle of coefficients of polynomials u(n,x) jointly generated with A210599; see the Formula section.at n=50A210598
• Triangle T(n, k) = Number of non-equivalent (mod D_3) ways to arrange k indistinguishable points on a triangular grid of side n so that no three points are collinear. Triangle read by rows.at n=53A234350
• Number of non-equivalent (mod D_3) ways to arrange 4 indistinguishable points on a triangular grid of side n so that no three points are collinear.at n=6A234352
• Triangle read by rows, Bell transform of Bell numbers.at n=50A264428
• Number of nonequivalent ways to place 3 points on an n X n square grid so that no more than 2 points are on a vertical or horizontal straight line.at n=9A279447
• Indices of primes followed by a gap (distance to next larger prime) of 44.at n=15A320720
• Irregular triangle read by rows where T(n,k) is the number of simple graphs covering n vertices with exactly k triangles, 0 <= k <= binomial(n,3).at n=54A372167