A322471 - OEIS

%I #8 Dec 10 2018 08:55:43

%S 2,3,5,7,11,19,23,29,31,41,43,47,53,59,61,67,71,79,83,101,103,107,137,

%T 163,167,173,179,181,191,193,199,211,223,229,233,239,241,263,269,281,

%U 283,317,331,347,349,353,367,373,383,389,401,431,443,449,461,467,479,491,509,547,557,563

%N Base-9 deletable primes (written in base 10).

%C A prime p is a base-b deletable prime if when written in base b it has the property that removing some digit leaves either the empty string or another deletable prime.

%C Deleting a digit cannot leave any leading zeros in the new string. For example, deleting the 2 in 2003 to obtain 003 is not allowed.

%H Robert Price, <a href="/A322471/b322471.txt">Table of n, a(n) for n = 1..327</a>

%t b = 9; d = {};

%t p = Select[Range[2, 10000], PrimeQ[#] &];

%t For[i = 1, i <= Length[p], i++,

%t c = IntegerDigits[p[[i]], b];

%t If[Length[c] == 1, AppendTo[d, p[[i]]]; Continue[]];

%t For[j = 1, j <= Length[c], j++,

%t t = Delete[c, j];

%t If[t[[1]] == 0, Continue[]];

%t If[MemberQ[d, FromDigits[t, b]], AppendTo[d, p[[i]]]; Break[]]]];

%t d (* _Robert Price_, Dec 09 2018 *)

%Y Cf. A080608, A080603, A096235-A096246.

%K nonn,base,easy

%O 1,1

%A _Robert Price_, Dec 09 2018