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

 

Logo
Hints
(Greetings from The On-Line Encyclopedia of Integer Sequences!)
A325069 Prime numbers congruent to 9 modulo 16 representable by x^2 + 32*y^2. 3

%I #16 Apr 12 2019 08:24:58

%S 41,137,313,409,457,521,569,761,809,857,953,1129,1321,1657,1993,2137,

%T 2153,2297,2377,2521,2617,2633,2713,2729,2777,2953,3001,3209,3433,

%U 3593,3769,3881,3929,4073,4441,4649,4729,4793,4889,4969,5273,5417,5449,5641,5657

%N Prime numbers congruent to 9 modulo 16 representable by x^2 + 32*y^2.

%C Kaplansky showed that prime numbers congruent to 9 modulo 16 are representable by exactly one of the quadratic forms x^2 + 32*y^2 or x^2 + 64*y^2. This sequence corresponds to those representable by the first form and A325070 to those representable by the second form.

%H David Brink, <a href="https://doi.org/10.1016/j.jnt.2008.04.007">Five peculiar theorems on simultaneous representation of primes by quadratic forms</a>, Journal of Number Theory 129(2) (2009), 464-468, doi:10.1016/j.jnt.2008.04.007, MR 2473893.

%H Rémy Sigrist, <a href="/A325069/a325069.gp.txt">PARI program for A325069</a>

%H Wikipedia, <a href="https://en.wikipedia.org/wiki/Kaplansky%27s_theorem_on_quadratic_forms">Kaplansky's theorem on quadratic forms</a>

%e Regarding 41:

%e - 41 is a prime number,

%e - 41 = 2*16 + 9,

%e - 41 = 3^2 + 32*1^2,

%e - hence 41 belongs to this sequence.

%o (PARI) See Links section.

%Y See A325067 for similar results.

%Y Cf. A105126.

%K nonn

%O 1,1

%A _Rémy Sigrist_, Mar 27 2019

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.

License Agreements, Terms of Use, Privacy Policy. .

Last modified May 11 18:41 EDT 2024. Contains 372413 sequences. (Running on oeis4.)