21801

Appears in sequences

• Numbers k such that the continued fraction for sqrt(k) has even period and if the last term of the periodic part is deleted the central term is 98.at n=36A031596
• 3 times 10-gonal (or decagonal) numbers: a(n) = 3*n*(4*n-3).at n=43A152767
• a(n) = n*(14*n + 13).at n=39A195028
• Numbers k such that (5*10^k + 37)/3 is prime.at n=22A281171
• a(n) = Sum_{k=0..n} binomial(2*k, k) * q(k), where q(k) is the number of partitions into distinct parts (A000009).at n=7A356270