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A050806 Inserting any digit between adjacent digits of prime p produces exactly 1 new prime. 3
101, 149, 163, 241, 269, 271, 317, 347, 367, 397, 409, 419, 443, 487, 509, 541, 587, 601, 641, 761, 787, 811, 821, 863, 907, 919, 1439, 1481, 1663, 1877, 2089, 2111, 2579, 2593, 2671, 2819, 2971, 3121, 3457, 3463, 3571, 3643, 3659, 3769, 3917, 4001 (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. 101 yields only one prime using digit '6' -> 1(6)0(6)1 -> prime 16061.

MATHEMATICA

aQ[n_]:=Plus@@Boole[PrimeQ[Table[FromDigits[Riffle[IntegerDigits[n], k]], {k, 0, 9}]]]==1; Select[Prime[Range[5, 555]], aQ[#]&] (* Jayanta Basu, May 30 2013 *)

PROG

(Haskell)

import Data.List (intersperse)

a050806 n = a050806_list !! (n-1)

a050806_list = filter ((== 1) . sum . 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, A050805.

Cf. A010051, A000040.

Sequence in context: A122531 A141871 A238503 * A243890 A129563 A141927

Adjacent sequences:  A050803 A050804 A050805 * A050807 A050808 A050809

KEYWORD

nonn,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 25 00:59 EDT 2019. Contains 323534 sequences. (Running on oeis4.)