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!)
A165502 Primes p where the digital sum of p^2 is equal to 31. 6
83, 137, 173, 223, 263, 277, 281, 367, 443, 457, 547, 587, 673, 677, 691, 727, 853, 857, 907, 911, 997, 1033, 1087, 1109, 1163, 1181, 1213, 1217, 1307, 1433, 1447, 1523, 1613, 1627, 1699, 1721, 1811, 2027, 2153, 2203, 2221, 2297, 2347, 2459, 2473, 2477, 2531, 2549 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

LINKS

Vincenzo Librandi, Table of n, a(n) for n = 1..1000

FORMULA

{A000040(i) : A123157(i) = 31} [R. J. Mathar, Sep 29 2009]

EXAMPLE

83 is in the sequence because 83^2=6889 and 6+8+8+9=31.

1721 is in the sequence because 1721^2=2961841 and 2+9+6+1+8+4+1=31.

MAPLE

A007953 := proc(n) add(d, d=convert(n, base, 10)) ; end:

A123157 := proc(n) A007953((ithprime(n))^2) ; end:

for n from 1 to 10000 do if A123157(n) = 31 then printf("%d, ", ithprime(n)) ; fi; od: # R. J. Mathar, Sep 29 2009

MATHEMATICA

Select[Prime[Range[500]], Total[IntegerDigits[#^2]]== 31 &] (* Harvey P. Dale, Apr 13 2011 *)

PROG

(Magma) [p: p in PrimesUpTo(2600) | &+Intseq(p^2) eq 31]; // Vincenzo Librandi, Sep 12 2013

CROSSREFS

Sequence in context: A210527 A140038 A260495 * A126711 A039548 A141976

Adjacent sequences: A165499 A165500 A165501 * A165503 A165504 A165505

KEYWORD

nonn,base

AUTHOR

Vincenzo Librandi, Sep 21 2009

EXTENSIONS

Edited by R. J. Mathar, Sep 29 2009

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 29 03:18 EST 2022. Contains 358422 sequences. (Running on oeis4.)