111860

Appears in sequences

• Numbers k such that k concatenated with k 1's is a prime.at n=21A068817
• a(n) = n*(n + 1)*(17*n - 14)/6.at n=34A237617
• a(n) = Sum_{d|n} d^2 * (d+1)/2.at n=57A278403
• Number of odd chordless cycles in the n-Andrásfai graph.at n=15A301771
• Triangle read by rows. T(n, k) = BellPolynomial(n, -k).at n=43A350263