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!)
 A105608 Sylvester dividends for A002605. 2
 1, 1, 1, 2, 1, 12, 1, 16, 6, 88, 1, 960, 1, 656, 264, 896, 1, 48960, 1, 53504, 1968, 36544, 1, 2795520, 44, 272768, 2448, 2980864, 1, 1547335680, 1, 2781184, 109632, 15196672, 14432, 8635760640, 1, 113429504, 818304, 8677064704, 1, 4808968273920, 1, 9252356096, 415337472, 6319476736, 1, 26795484119040, 328, 3584860454912 (list; graph; refs; listen; history; text; internal format)
 OFFSET 1,4 LINKS Eric Weisstein's World of Mathematics, Sylvester Cyclotomic Number. FORMULA a(n) = A002605(n)/A105607(n); a(n) = Product_{k=1..n-1, if(gcd(n, k)>1, (1+sqrt(3))-(1-sqrt(3))*exp(2*Pi*I*k/n), 1)}, I=sqrt(-1), MATHEMATICA f[n_] := FullSimplify[ Expand[ Times @@ ((1+Sqrt[3])-(1-Sqrt[3])*Exp[2Pi*I*Select[Range[n], GCD[ #, n] == 1 &]/n])]]; Table[ f[n], {n, 2, 32] (* Robert G. Wilson v, Aug 02 2005 *) CROSSREFS Cf. A105607, A105609. Sequence in context: A128247 A161150 A163088 * A051190 A072512 A271531 Adjacent sequences:  A105605 A105606 A105607 * A105609 A105610 A105611 KEYWORD easy,nonn AUTHOR Paul Barry, Apr 15 2005 EXTENSIONS More terms from David Wasserman, May 06 2008 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 June 17 17:05 EDT 2021. Contains 345085 sequences. (Running on oeis4.)