18086805002domain: NAppears in sequencesINVERTi transform of central trinomial coefficients (A002426).at n=27A007971Expansion of 1 - x - sqrt(1 - 2*x - 3*x^2) in powers of x.at n=27A126068Expansion of 2 - x - sqrt(1-2x-3x^2).at n=27A168055