A179025 Primes with a single 2 as the only prime digit.

2, 29, 211, 241, 269, 281, 421, 821, 829, 929, 1021, 1129, 1201, 1249, 1289, 1291, 1429, 1621, 2011, 2069, 2081, 2089, 2099, 2111, 2141, 2161, 2411, 2441, 2609, 2689, 2699, 2801, 2819, 2861, 2909, 2969, 2999, 4021, 4129, 4201, 4211, 4219, 4241, 4261

Offset

1,1

Comments

This is a proper subsequence of A179024. - Jianing Song, Jul 10 2018

Links

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

Maple

Digs:= [0, 1, 2, 4, 6, 8, 9]:
f:= proc(n) local L, x;
  L:= convert(n, base, 7);
  if numboccur(2, L) <> 1 then return NULL fi;
  x:= add(Digs[L[i]+1]*10^(i-1), i=1..nops(L));
  if isprime(x) then x fi
end proc:
map(f, [$1..2000]); # Robert Israel, Jul 10 2018

Mathematica

Select[Prime[Range[600]], DigitCount[#, 10, 2]==1&&NoneTrue[ DeleteCases[ IntegerDigits[#], 2], PrimeQ]&] (* Harvey P. Dale, Feb 20 2022 *)

Crossrefs

Cf. A179024.

Sequence in context: A342454 A009772 A179024 * A377627 A244599 A261268

Adjacent sequences: A179022 A179023 A179024 * A179026 A179027 A179028

Keyword

nonn,base

Author

Lekraj Beedassy, Jun 25 2010

Extensions

Terms confirmed by Ray Chandler, Jul 13 2010

Definition clarified by Harvey P. Dale, Feb 20 2022

Status

approved