

A156121


First prime of a pair, formed by concatenating n, n+1, the second prime (not shown) formed by concatenating n+2, n+3.


2



67, 7879, 9091, 186187, 276277, 426427, 438439, 450451, 600601, 606607, 798799, 816817, 858859, 936937, 960961, 11401141, 13981399, 15361537, 17461747, 17881789, 18961897, 21002101, 21902191, 22082209, 27362737, 28802881
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OFFSET

1,1


LINKS

Harvey P. Dale, Table of n, a(n) for n = 1..1000


EXAMPLE

For n=6 the primes generated are 67 and 89 so 67 is in the sequence.


MATHEMATICA

fd[lst_]:=FromDigits[Flatten[IntegerDigits/@lst]]; ppcQ[n_]:=And@@ PrimeQ[ {fd[{n, n+1}], fd[{n+2, n+3}]}]; fd[{#, #+1}]&/@Select[Range[10000], ppcQ] (* Harvey P. Dale, Aug 07 2013 *)


CROSSREFS

Sequence in context: A261974 A328353 A078989 * A280004 A211961 A144940
Adjacent sequences: A156118 A156119 A156120 * A156122 A156123 A156124


KEYWORD

nonn,base


AUTHOR

Ki Punches, Feb 16 2009


EXTENSIONS

Edited and extended by Ray Chandler, Feb 20 2009


STATUS

approved



