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A032683 Numbers n such that n surrounded by digit '3' is a prime. 2
1, 5, 7, 8, 16, 20, 25, 31, 32, 34, 37, 41, 43, 46, 53, 58, 59, 61, 62, 64, 67, 73, 79, 80, 82, 83, 85, 86, 92, 94, 101, 103, 106, 112, 115, 118, 119, 122, 125, 133, 139, 151, 154, 157, 158, 164, 166, 172, 179, 187, 188, 196, 197, 200, 206, 208, 214, 217 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,2

LINKS

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

MATHEMATICA

Select[Range[250], PrimeQ[FromDigits[Join[{3}, IntegerDigits[#], {3}]]]&] (* Harvey P. Dale, Apr 18 2012 *)

CROSSREFS

Cf. A032687.

Sequence in context: A171952 A238011 A140237 * A182005 A192285 A192123

Adjacent sequences:  A032680 A032681 A032682 * A032684 A032685 A032686

KEYWORD

nonn,base

AUTHOR

Patrick De Geest, May 15 1998

STATUS

approved

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Last modified April 15 07:59 EDT 2021. Contains 342975 sequences. (Running on oeis4.)