login

Year-end appeal: Please make a donation to the OEIS Foundation to support ongoing development and maintenance of the OEIS. We are now in our 61st year, we have over 378,000 sequences, and we’ve reached 11,000 citations (which often say “discovered thanks to the OEIS”).

A030629
Numbers with 11 divisors.
37
1024, 59049, 9765625, 282475249, 25937424601, 137858491849, 2015993900449, 6131066257801, 41426511213649, 420707233300201, 819628286980801, 4808584372417849, 13422659310152401
OFFSET
1,1
COMMENTS
Let p be a prime. Then the n-th number with p divisors is equal to prime(n)^(p-1). - Omar E. Pol, May 06 2008
FORMULA
a(n) = A000040(n)^10, i.e. tenth power of n-th prime. - Henry Bottomley, Aug 20 2001
From Amiram Eldar, Jan 24 2021: (Start)
Product_{n>=1} (1 + 1/a(n)) = zeta(10)/zeta(20) = 16368226875/(174611*Pi^10) = A013668/A013678.
Product_{n>=1} (1 - 1/a(n)) = 1/zeta(10) = 93555/Pi^10 = 1/A013668. (End)
MATHEMATICA
(Prime@Range@30)^10 (* Vladimir Joseph Stephan Orlovsky, Apr 11 2011 *)
PROG
(Sage)
[p**10 for p in prime_range(100)]
# Zerinvary Lajos, May 16 2007
(Magma) [p^10: p in PrimesUpTo(300)]; // Vincenzo Librandi, Mar 27 2014
(PARI) is(n)=isprimepower(n)==10 \\ Charles R Greathouse IV, Jun 19 2016
(Python)
from sympy import prime
def A030629(n): return prime(n)**10 # Chai Wah Wu, Sep 13 2024
KEYWORD
nonn,easy
AUTHOR
STATUS
approved