a(n) = (5*n)^5.

Terms

a(0) =0a(1) =3125a(2) =100000a(3) =759375a(4) =3200000a(5) =9765625a(6) =24300000a(7) =52521875a(8) =102400000a(9) =184528125a(10) =312500000a(11) =503284375a(12) =777600000a(13) =1160290625a(14) =1680700000a(15) =2373046875a(16) =3276800000a(17) =4437053125a(18) =5904900000a(19) =7737809375a(20) =10000000000a(21) =12762815625a(22) =16105100000a(23) =20113571875a(24) =24883200000