Hi,

A twist on the old x^y - y^x prime search is x^r + a where r is the reverse

of the digits of x and a is an integer. See Pari code below

For example

g(1000,2)

0,1,3,39,51,87,113,737,831,

737^737+2 is a 2114 digit prime

[PRIMO - Task Report]

Version=3.0.7

WebSite=

http://www.ellipsa.net/
Task=Certification

ID=B31C802C933B8

Created=08/21/2009 12:59:00 PM

[Common]

Path=C:\primo\

Selected=1

Processed=1

Certified=1

Candidate #1=Certified, 18h 53mn 59s

[Candidate #1]

Input=737to737+2.in

Report=primo-B31C802C933B8-001.cr

Output=primo-B31C802C933B8-001.out

Status=Candidate certified prime

Pari code

g(n,a) = for(x=0,n,r=eval(rev(x));y=x^r+a;if(ispseudoprime(y),print1(x",")))

rev(str)=local(tmp,s,j);tmp=Vec(Str(str));s="";forstep(j=length(tmp),1,-1,

s=concat(s,tmp[j]));return(s)

Cino

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