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!)
A153048 Numbers n with property that n^2 is a concatenation of two 3-digit primes. 5

%I

%S 319,337,357,363,371,387,409,447,591,663,681,701,801,827,893

%N Numbers n with property that n^2 is a concatenation of two 3-digit primes.

%C There are exactly 15 such numbers.

%e Corresponding squares are: 101761, 113569, 127449, 131769, 137641, 149769, 167281, 199809, 349281, 439569, 463761, 491401, 641601, 683929, 797449.

%t c = 0; t = 1000; re = Sort[Reap[Do[If[PrimeQ[p], Do[If[PrimeQ[q], r = p*t + q; s = Sqrt[r]; If[s == Floor[s], c++; Sow[s]]], {q, 101, 999, 2}]], {p, 101, 999, 2}]][[2, 1]]]

%K fini,full,nonn,base

%O 1,1

%A _Zak Seidov_, Dec 17 2008

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 October 5 08:29 EDT 2022. Contains 357252 sequences. (Running on oeis4.)