The OEIS Foundation is supported by donations from users of the OEIS and by a grant from the Simons Foundation. Hints (Greetings from The On-Line Encyclopedia of Integer Sequences!)
 A218150 5^((6+5*n+n^3)/6). 2
 1, 5, 25, 625, 390625, 30517578125, 1490116119384765625, 227373675443232059478759765625, 542101086242752217003726400434970855712890625, 100974195868289511092701256356196637398170423693954944610595703125 (list; graph; refs; listen; history; text; internal format)
 OFFSET -1,2 COMMENTS a(n) = a(0) * product(i=1,2,...k) r(i)^C(n,i), C(n,i)=0 for all i > n. 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. LINKS FORMULA a(n) = a(n-1)*(2^(1+n*(n-1)/2)), with a(0)=5. EXAMPLE a(3) = 5^((6+5*3+3^3)/6) = 5^((6+15+27)/6) = 5^(48/6) = 5^8 = 390625. PROG (Maxima) A218150(n):=5^((6+5*n+n^3)/6)\$ makelist(A218150(n), n, -1, 9); /* Martin Ettl, Oct 31 2012 */ (PARI) a(n)=5^(n*(n^2+5)/6+1) \\ Charles R Greathouse IV, Jan 06 2013 CROSSREFS Sequence in context: A030995 A067270 A215118 * A176594 A274463 A279835 Adjacent sequences:  A218147 A218148 A218149 * A218151 A218152 A218153 KEYWORD nonn,easy AUTHOR Mokhtar Mohamed, Oct 22 2012 STATUS approved

Lookup | Welcome | Wiki | Register | Music | Plot 2 | Demos | Index | Browse | More | WebCam
Contribute new seq. or comment | Format | Style Sheet | Transforms | Superseeker | Recent
The OEIS Community | Maintained by The OEIS Foundation Inc.

Last modified October 21 19:16 EDT 2021. Contains 348155 sequences. (Running on oeis4.)