The OEIS is supported by the many generous donors to the OEIS Foundation.

 Hints (Greetings from The On-Line Encyclopedia of Integer Sequences!)
 A097707 Part of n! composed of prime factors of form 4k+3. 0
 1, 1, 3, 3, 3, 9, 63, 63, 567, 567, 6237, 18711, 18711, 130977, 392931, 392931, 392931, 3536379, 67191201, 67191201, 1411015221, 15521167431, 356986850913, 1070960552739, 1070960552739, 1070960552739, 28915934923953 (list; graph; refs; listen; history; text; internal format)
 OFFSET 1,3 COMMENTS log(a(n)) ~ 1/2 log n!. LINKS P. Pollack, Analytic and Combinatorial Number Theory Course Notes, p. 75. [?Broken link] P. Pollack, Analytic and Combinatorial Number Theory Course Notes, p. 75. PROG (PARI) a(n)=local(f); f=factor(n!); prod(k=1, matsize(f)[1], if(f[k, 1]%4<>3, 1, f[k, 1]^f[k, 2])) CROSSREFS Equals A097706(A000142(n)). Sequence in context: A299189 A231651 A160589 * A240533 A115282 A321507 Adjacent sequences: A097704 A097705 A097706 * A097708 A097709 A097710 KEYWORD nonn AUTHOR Ralf Stephan, Aug 30 2004 EXTENSIONS Typo in PARI code fixed by Colin Barker, Mar 12 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 | Recents
The OEIS Community | Maintained by The OEIS Foundation Inc.

Last modified March 28 05:31 EDT 2023. Contains 361577 sequences. (Running on oeis4.)