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A214702
Primes of the form XYYYYX, where Y is a single digit.
3
100333331003, 100388881003, 100733331007, 100766661007, 100999991009, 101333331013, 101377771013, 101755551017, 102155551021, 102722221027, 102733331027, 102922221029, 102944441029, 103133331031, 103177771031, 103199991031, 103322221033, 103366661033
OFFSET
1,1
LINKS
MATHEMATICA
f[n_]:=Block[{len=Floor[Log[10, n]+1]}, Select[10^(4+len) n+10^len*Table[k (10^4-1)/9, {k, 9}]+n, PrimeQ@#&]]; Array[f, 3509]//Flatten
PROG
(Magma) m:=4; [p: d in [1..9], n in [1..2000 by 2] | IsPrime(p) where p is n*(10^(m+t)+1)+d*10^t*(10^m-1) div 9 where t is #Intseq(n)]; // Vincenzo Librandi, Sep 14 2013
CROSSREFS
KEYWORD
nonn,base
AUTHOR
Vincenzo Librandi, Jul 27 2012
STATUS
approved