159251

Appears in sequences

• Pentagonal numbers (A000326) that are also brilliant numbers (A078972).at n=19A113941
• a(n) is the first pentagonal number that is nontrivially the sum of two pentagonal numbers of the type P(p) + P(p+n) (we always have P(k) = P(0) + P(k)).at n=11A133312
• Smallest number m such that prime(n) is a factor of both m and sigma(m).at n=37A156099
• Semiprimes of the form n*(3*n-1)/2.at n=33A245365
• Semiprimes of the form p(6p - 1).at n=20A330409