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A179033 Emirps with a single 2 as the only prime digit. 2
1021, 1201, 1249, 1429, 9029, 9209, 9241, 9421, 10429, 11621, 12109, 12119, 12149, 12491, 12611, 12619, 12641, 12689, 12809, 12841, 12919, 14029, 14621, 14629, 14821, 14929, 16249, 16829, 18269, 19219, 19249, 19421, 90121, 90821, 91121 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

LINKS

Robert Israel, Table of n, a(n) for n = 1..10000

EXAMPLE

Note that 2 and 929 are not emirps because they are palindromes.

MAPLE

Dmax:= 6: # to get all terms with up to Dmax digits

Res:= NULL:

npd:= [0, 1, 4, 6, 8, 9]:

for dd from 3 to Dmax do

  R:= [seq(seq([seq(npd[j+1], j=convert(6*x+j, base, 6))],

    x=[$6^(dd-3) .. 2*6^(dd-3)-1, $5*6^(dd-3)..6^(dd-2)-1]), j=[1, 5])];

  for p from 2 to dd-1 do

    for r in R do

      x:= [op(r[1..p-1]), 2, op(r[p..-1])];

      v1:= add(x[i]*10^(i-1), i=1..dd);

      v2:= add(x[-i]*10^(i-1), i=1..dd);

      if v1 < v2 and isprime(v1) and isprime(v2) then Res:= Res, v1, v2; if min(v1, v2) < 10^3  then print(dd, p, r, x, v1, v2) fi fi

od od od:

sort([Res]); # Robert Israel, Jun 02 2016

MATHEMATICA

emrp[n_]:=Module[{idn=IntegerDigits[n], rev}, rev=Reverse[idn]; PrimeQ[FromDigits[rev]]&&rev!=idn]

only2[n_]:=DigitCount[n, 10, {3, 5, 7}]=={0, 0, 0}&&DigitCount[n, 10, 2]==1

Select[Select[Prime[Range[10000]], emrp], only2] (* Harvey P. Dale, Jan 22 2011 *)

CROSSREFS

Cf. A006567, A179032.

Sequence in context: A088290 A209620 A179032 * A082059 A081633 A020388

Adjacent sequences:  A179030 A179031 A179032 * A179034 A179035 A179036

KEYWORD

base,less,nonn

AUTHOR

Lekraj Beedassy, Jun 25 2010

EXTENSIONS

Terms confirmed by Ray Chandler, Jul 13 2010

Definition improved by Harvey P. Dale, Jul 17 2010

STATUS

approved

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Last modified February 20 04:46 EST 2020. Contains 332063 sequences. (Running on oeis4.)