21913

Appears in sequences

• Sum of n plus its prime factors associated with A020700.at n=28A020905
• Number of consecutive prime runs of 8 primes congruent to 3 mod 4 below 10^n.at n=8A092658
• Number of intersection points of all lines through pairs of vertices of a regular n-gon.at n=21A146212
• Number of 5-bead necklaces labeled with numbers -n..n not allowing reversal, with sum zero and first differences in -n..n.at n=14A208996
• Numbers k such that A339549(k) = A339549(k+1).at n=21A339550
• A146212(2*n).at n=10A347321
• a(n) = (prime(n) + prime(n+2))^2 + prime(n+1)^2.at n=17A348569
• Number of vertices in graph G_n formed by taking a regular n-gon with all its chords extended to infinity (the n-th graph in A344857) and inverting it in its circumscribing circle.at n=21A383461