19233

Appears in sequences

• Numbers k such that 2*10^k - 1 is prime.at n=24A002957
• a(n) = Sum_{k=0..n-1} T(n,k) * T(n,k+1), with T given by A026780.at n=6A027248
• Partial sums of 3-almost primes which are again 3-almost primes, i.e., have exactly 3 not necessarily distinct prime factors.at n=27A217018
• Number of partitions of n with difference 4 between the number of odd parts and the number of even parts, both counted without multiplicity.at n=41A242695