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A050805 Inserting any digit between adjacent digits of prime p never yields another prime. 3
439, 853, 1013, 1061, 1109, 1117, 1153, 1187, 1213, 1249, 1259, 1283, 1291, 1301, 1303, 1361, 1427, 1451, 1489, 1511, 1523, 1531, 1583, 1597, 1607, 1657, 1733, 1747, 1753, 1801, 1873, 1879, 1913, 1951, 2069, 2083, 2137, 2243, 2251, 2267, 2293, 2297 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

LINKS

Reinhard Zumkeller, Table of n, a(n) for n = 1..10000

EXAMPLE

E.g. 437 yields these ten composites -> 40307, 41317, 42327, 43337, 44347, 45357, 46367, 47377, 48387, 49397.

MATHEMATICA

a[n_]:=Or@@PrimeQ[Table[FromDigits[Riffle[IntegerDigits[n], k]], {k, 0, 9}]]; Select[Prime[Range[5, 350]], a[#]==False&] (* Jayanta Basu, May 30 2013 *)

PROG

(Haskell)

import Data.List (intersperse)

a050805 n = a050805_list !! (n-1)

a050805_list = filter ((all (== 0)) . f) a000040_list where

   f p = map (i $ show p) "0123456789"

   i ps d = a010051' (read $ intersperse d ps :: Integer)

-- Reinhard Zumkeller, May 07 2013

CROSSREFS

Cf. A050674-A050719, A050806.

Cf. A010051, A000040.

Sequence in context: A185683 A142753 A142141 * A252135 A157737 A061328

Adjacent sequences:  A050802 A050803 A050804 * A050806 A050807 A050808

KEYWORD

nonn,nice,base

AUTHOR

Patrick De Geest, Oct 15 1999

EXTENSIONS

Offset corrected by Reinhard Zumkeller, May 07 2013

STATUS

approved

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Last modified May 22 05:03 EDT 2019. Contains 323473 sequences. (Running on oeis4.)