nth term of the series 1+45+752+1053+…will be

The given series  is  clearly  an  AG,  the corresponding  AP is 1+4+7+10+… having  nth term = 3n−2.and corresponding GP is  1+15+152+… having  nth term =15n−1Hence,  required  nth term of the  series  is 3n−25n−1.