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A032628 Primes that are concatenations of n with n + 5. 1
1217, 1621, 1823, 2833, 4651, 6469, 7681, 7883, 8287, 8893, 102107, 126131, 132137, 138143, 148153, 154159, 178183, 184189, 186191, 196201, 208213, 214219, 226231, 228233, 234239, 246251, 264269, 282287, 288293, 298303 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

LINKS

Harvey P. Dale, Table of n, a(n) for n = 1..600

MATHEMATICA

concatQ[n_]:=Module[{idn=IntegerDigits[n], len}, len=Length[idn]; EvenQ[ len]&&FromDigits[Take[idn, -len/2]]-FromDigits[Take[idn, len/2]]==5]; Select[Prime[Range[30000]], concatQ] (* Harvey P. Dale, Jul 30 2015 *)

CROSSREFS

Cf. A032610, A032620.

Sequence in context: A059287 A225759 A059669 * A175964 A300408 A252600

Adjacent sequences:  A032625 A032626 A032627 * A032629 A032630 A032631

KEYWORD

nonn,base

AUTHOR

Patrick De Geest, May 15 1998

EXTENSIONS

Edited by Charles R Greathouse IV, Apr 28 2010

STATUS

approved

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Last modified June 19 05:33 EDT 2019. Contains 324218 sequences. (Running on oeis4.)