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!)
 A278509 a(n) = 3^{number of primes congruent to 3 modulo 4 dividing n (with multiplicity)}. 3
 1, 1, 3, 1, 1, 3, 3, 1, 9, 1, 3, 3, 1, 3, 3, 1, 1, 9, 3, 1, 9, 3, 3, 3, 1, 1, 27, 3, 1, 3, 3, 1, 9, 1, 3, 9, 1, 3, 3, 1, 1, 9, 3, 3, 9, 3, 3, 3, 9, 1, 3, 1, 1, 27, 3, 3, 9, 1, 3, 3, 1, 3, 27, 1, 1, 9, 3, 1, 9, 3, 3, 9, 1, 1, 3, 3, 9, 3, 3, 1, 81, 1, 3, 9, 1, 3, 3, 3, 1, 9, 3, 3, 9, 3, 3, 3, 1, 9, 27, 1, 1, 3, 3, 1, 9, 1, 3, 27, 1, 3, 3, 3, 1, 9, 3, 1, 9, 3, 3, 3 (list; graph; refs; listen; history; text; internal format)
 OFFSET 1,3 COMMENTS Fully multiplicative with a(p^e) = 1 if p = 2, (p mod 4)^e if p > 2. LINKS Antti Karttunen, Table of n, a(n) for n = 1..10000 FORMULA a(n) = A065338(A000265(n)) = A000265(A065338(n)). a(n) = A000244(A065339(n)) = 3^A065339(n). PROG (Scheme) (define (A278509 n) (A065338 (A000265 n))) CROSSREFS Cf. A000244, A000265, A065338, A065339. Cf. also A278265. Sequence in context: A336456 A227898 A035649 * A094782 A035666 A060592 Adjacent sequences:  A278506 A278507 A278508 * A278510 A278511 A278512 KEYWORD nonn,mult AUTHOR Antti Karttunen, Nov 28 2016 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 14 06:59 EDT 2021. Contains 342946 sequences. (Running on oeis4.)