Logo

Greetings from The On-Line Encyclopedia of Integer Sequences!

Hints

Search: id:A033205
Displaying 1-1 of 1 results found. page 1
     Format: long | short | internal | text      Sort: relevance | references | number      Highlight: on | off
A033205 Primes of form x^2+5*y^2. +0
13
5, 29, 41, 61, 89, 101, 109, 149, 181, 229, 241, 269, 281, 349, 389, 401, 409, 421, 449, 461, 509, 521, 541, 569, 601, 641, 661, 701, 709, 761, 769, 809, 821, 829, 881, 929, 941, 1009, 1021, 1049, 1061, 1069 (list; graph; listen)
OFFSET

1,1

COMMENT

Primes congruent to 1,5,9 modulo 20. - Michael Somos Aug 13 2006

Or, 5 and all primes p that divide Fibonacci[(p-1)/2] = A121568[n]. - Alexander Adamchuk (alex(AT)kolmogorov.com), Aug 07 2006

Except for 5, also primes of the form x^2+25y^2. See A140633. - T. D. Noe (noe(AT)sspectra.com), May 19 2008

REFERENCES

D. Cox, "Primes of Form x^2 + n y^2", Wiley, 1989.

LINKS

B. W. Brewer, On primes of the form u^2+5v^2, Am. Math. Monthly vol. 17 no 2 (1966) pp 502-509.

FORMULA

A020669 INTERSECT A000040.

CROSSREFS

Cf. A121568.

Cf. A139643.

Sequence in context: A115279 A087879 A091729 this_sequence A107151 A117746 A081116

Adjacent sequences: A033202 A033203 A033204 this_sequence A033206 A033207 A033208

KEYWORD

nonn

AUTHOR

njas

page 1

Search completed in 0.002 seconds

Lookup | Welcome | Find friends | Music | Plot 2 | Demos | Index | Browse | More | WebCam
Contribute new seq. or comment | Format | Transforms | Puzzles | Hot | Classics
More pages | Superseeker | Maintained by N. J. A. Sloane (njas@research.att.com)

Last modified July 4 13:19 EDT 2008. Contains 140839 sequences.


AT&T Labs Research