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Base-5 deletable primes (written in base 10).
2

%I #12 Dec 06 2018 19:24:41

%S 2,3,7,11,13,17,19,23,37,47,53,59,61,67,71,73,79,89,97,103,107,113,

%T 137,197,227,239,263,269,271,307,311,317,337,347,353,359,367,373,379,

%U 389,397,439,449,479,487,503,523,547,557,563,569,571,607,613,677,727,739,887,947,977

%N Base-5 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="/A321700/b321700.txt">Table of n, a(n) for n = 1..1511</a>

%t b = 5; 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 06 2018 *)

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

%K nonn,base,easy

%O 1,1

%A _Robert Price_, Nov 17 2018