112477domain: NAppears in sequencesPentagonal numbers (A000326) that are also brilliant numbers (A078972).at n=15A113941Pentagonal numbers for which the sum of the digits is also a pentagonal number.at n=29A117709Semiprimes of the form n*(3*n-1)/2.at n=29A245365Semiprimes of the form p(6p - 1).at n=18A330409