N.PYT
    << 1 1 -> n s t
      << 'FLOOR((3+sqrt(8*n-7))/2)'
        EVAL 't' STO
        'n-(t^2-3*t +2)/2'
        EVAL 's' STO
        2 s t * *
        t SQ s SQ -
        t SQ s SQ +
        3 ->LIST
      >>
    >>