%I #15 Feb 27 2013 09:48:51
%S 1,5,25,625,390625,30517578125,1490116119384765625,
%T 227373675443232059478759765625,
%U 542101086242752217003726400434970855712890625,100974195868289511092701256356196637398170423693954944610595703125
%N 5^((6+5*n+n^3)/6).
%C a(n) = a(0) * product(i=1,2,...k) r(i)^C(n,i), C(n,i)=0 for all i > n.
%C Here, it is submitted a special case of the geometric-geometric sequence having finite ratios, that is, k consecutive rows of ratios, whose first terms are r(1), r(2), r(3),..., r(k), the last row (k-th row) being of a constant ratio, with k=3, a(0) = r(1) = r(2) = r(3) = 5.
%F a(n) = a(n-1)*(2^(1+n*(n-1)/2)), with a(0)=5.
%e a(3) = 5^((6+5*3+3^3)/6) = 5^((6+15+27)/6) = 5^(48/6) = 5^8 = 390625.
%o (Maxima) A218150(n):=5^((6+5*n+n^3)/6)$
%o makelist(A218150(n),n,-1,9); /* _Martin Ettl_, Oct 31 2012 */
%o (PARI) a(n)=5^(n*(n^2+5)/6+1) \\ _Charles R Greathouse IV_, Jan 06 2013
%K nonn,easy
%O -1,2
%A _Mokhtar Mohamed_, Oct 22 2012