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!)
 A090901 a(n) = floor[geometric mean of first n factorials]. 2
 1, 1, 2, 4, 8, 17, 38, 91, 230, 605, 1661, 4735, 13998, 42795, 135021, 438826, 1466690, 5033778, 17716515, 63865399, 235547709, 887938469, 3418054843, 13424588130, 53753996494, 219278318407, 910679550679, 3848136018924, 16534775039068, 72206065899240 (list; graph; refs; listen; history; text; internal format)
 OFFSET 1,3 LINKS Peter Luschny and Jon E. Schoenfield, Table of n, a(n) for n = 1..871 (First 100 terms from Peter Luschny) FORMULA a(n) = floor(A000178(n)^(1/n)). MAPLE a := n -> mul(k!^(1/n), k=1..n): prec := n -> max(10, ceil(log(2*Pi*n)/2+n*(log(n/exp(1))))): seq(floor(evalf(a(n), prec(n))), n=1..100); # Peter Luschny, Nov 27 2015 MATHEMATICA Module[{nn=30, fs}, fs=Range[nn]!; Table[Floor[GeometricMean[Take[fs, n]]], {n, nn}]] (* Harvey P. Dale, Nov 27 2015 *) PROG (PARI) a(n) = default(realprecision, 2*n); floor(prod(i=2, n, i!)^(1/n)); vector(500, n, a(n)) \\ Altug Alkan, Nov 27 2015 (MAGMA) a:=[]; f:=1; P:=1; for n in [1..100] do f*:=n; P*:=f; g:=Floor(P^(1/n)); while true do d:=g^n-P; if d gt 0 then g-:=Ceiling((1.0*d)*g/P/n); else d:=P-(g+1)^n; if d ge 0 then g+:=Ceiling((1.0*d)*g/P/n); else break; end if; end if; end while; a[n]:=g; end for; a; // Jon E. Schoenfield, Nov 27 2015 (Sage) def a(n): # Throws an error if result could not be computed exactly.     prec = max(53, ceil(0.75*ceil((log(2*pi*n)/2+n*(log(n/exp(1)))))))     rif = RealIntervalField(prec)     r = rif(prod(factorial(k)^(1/n) for k in (1..n)))     return r.unique_floor() [a(n) for n in (1..100)] # Peter Luschny, Nov 28 2015 CROSSREFS Cf. A090902. Sequence in context: A086615 A081124 A340776 * A101516 A118928 A325921 Adjacent sequences:  A090898 A090899 A090900 * A090902 A090903 A090904 KEYWORD nonn AUTHOR Amarnath Murthy, Dec 12 2003 EXTENSIONS Corrected and extended by N. J. A. Sloane, Oct 26 2004 More terms from Emeric Deutsch, Apr 13 2005 Corrected by Harvey P. Dale, Nov 27 2015 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 April 15 09:32 EDT 2021. Contains 342977 sequences. (Running on oeis4.)