login
This site is supported by donations to The OEIS Foundation.

 

Logo


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

Table of n, a(n) for n=1..27.

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: A180439 A231651 A160589 * A240533 A115282 A147605

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 | Recent | More pages
The OEIS Community | Maintained by The OEIS Foundation Inc.

License Agreements, Terms of Use, Privacy Policy .

Last modified March 25 07:34 EDT 2017. Contains 284047 sequences.