login
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
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 A370193
KEYWORD
nonn
AUTHOR
Ralf Stephan, Aug 30 2004
EXTENSIONS
Typo in PARI code fixed by Colin Barker, Mar 12 2015
STATUS
approved