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

 

Logo

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 59th year, we have over 358,000 sequences, and we’ve crossed 10,300 citations (which often say “discovered thanks to the OEIS”).

Other ways to Give
Hints
(Greetings from The On-Line Encyclopedia of Integer Sequences!)
A108325 "Binary prime squares": values of k for which k^2, expressed in base two and read as a decimal number, is a prime. 4
29, 39, 51, 53, 67, 85, 87, 107, 135, 181, 189, 235, 253, 297, 351, 375, 379, 445, 449, 493, 583, 599, 613, 701, 715, 725, 739, 749, 769, 781, 831, 841, 847, 853, 921, 953, 1007, 1093, 1273, 1339, 1443, 1511, 1543, 1569, 1575, 1587, 1619, 1681, 1697, 1705 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

LINKS

Harvey P. Dale, Table of n, a(n) for n = 1..1000

EXAMPLE

a(3)=51 because 51^2 = 2601 is the third perfect square whose binary representation 101000101001 read as the decimal one 101000101001 is prime.

MAPLE

a:=proc(n) if isprime(convert(n^2, binary))=true then n else fi end: seq(a(n), n=1..2400); # Emeric Deutsch, Jul 04 2005

MATHEMATICA

Select[Range[1800], PrimeQ[FromDigits[IntegerDigits[#^2, 2]]]&] (* Harvey P. Dale, May 23 2021 *)

PROG

(PARI) isok(n) = isprime(fromdigits(binary(n^2))); \\ Michel Marcus, Sep 24 2018

CROSSREFS

Cf. A108322, A108323, A108324.

Sequence in context: A166311 A159888 A159887 * A242555 A101007 A253252

Adjacent sequences: A108322 A108323 A108324 * A108326 A108327 A108328

KEYWORD

easy,nonn,base

AUTHOR

Alexandre Wajnberg, Jun 30 2005

EXTENSIONS

More terms from Emeric Deutsch, Jul 04 2005

STATUS

approved

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 November 27 06:50 EST 2022. Contains 358362 sequences. (Running on oeis4.)