19702

Appears in sequences

• a(n) = (Lucas(2*n) - Lucas(n))/2.at n=11A049681
• Numbers n such that 6*10^n + 3*R_n - 2 is prime, where R_n = 11...1 is the repunit (A002275) of length n.at n=25A103032
• a(n) = (n^3 + 3*n - 2)/2.at n=33A132127
• a(n) = A142710(n)/2.at n=11A147586
• Expansion of g.f. 1/((1 - x)^2*(1 - 3*x + 3*x^2)).at n=15A279231
• Numbers k such that (23*10^k - 143)/3 is prime.at n=22A281167
• Number of free holey polyominoes of n cells with simply-connected interiors.at n=12A359520