A214291 Primes of the form XYYYYYX, where Y is a single digit.

1333331, 1444441, 1777771, 3222223, 3444443, 7666667, 9222229, 9888889, 134444413, 136666613, 137777713, 191111119, 196666619, 197777719, 232222223, 295555529, 311111131, 319999931, 331111133, 379999937, 392222239, 394444439

Offset

1,1

Links

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

Mathematica

f[n_]:=Block[{len=Floor[Log[10, n]+1]}, Select[10^(5+len) n+10^len*Table[k (10^5-1)/9, {k, 9}]+n, PrimeQ@#&]]; Array[f, 3509]//Flatten

Prog

(Magma) m:=5; [p: d in [1..9], n in [1..50 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)]; // Bruno Berselli, Sep 12 2013

Crossrefs

Cf. A154270, A162423, A214290.

Sequence in context: A204969 A237107 A206620 * A023047 A206254 A157854

Adjacent sequences: A214288 A214289 A214290 * A214292 A214293 A214294

Keyword

nonn,base

Author

Vincenzo Librandi, Jul 26 2012

Status

approved