

A321701


Primes that are not base5 deletable primes (written in base 10).


1



5, 29, 31, 41, 43, 83, 101, 109, 127, 131, 139, 149, 151, 157, 163, 167, 173, 179, 181, 191, 193, 199, 211, 223, 229, 233, 241, 251, 257, 277, 281, 283, 293, 313, 331, 349, 383, 401, 409, 419, 421, 431, 433, 443, 457, 461, 463, 467, 491, 499, 509, 521, 541, 577, 587, 593, 599
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OFFSET

1,1


COMMENTS

A prime p is a baseb 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.
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.
Complement of all primes and A321700.


LINKS



MATHEMATICA

b = 5; d = {};
p = Select[Range[2, 10000], PrimeQ[#] &];
For[i = 1, i <= Length[p], i++,
c = IntegerDigits[p[[i]], b];
If[Length[c] == 1, AppendTo[d, p[[i]]]; Continue[]];
For[j = 1, j <= Length[c], j++,
t = Delete[c, j];
If[t[[1]] == 0, Continue[]];
If[MemberQ[d, FromDigits[t, b]], AppendTo[d, p[[i]]]; Break[]]]]; Complement[Table[Prime[n], {n, PrimePi[Last[d]]}], d] (* Robert Price, Dec 06 2018 *)


CROSSREFS



KEYWORD

nonn,base,easy


AUTHOR



STATUS

approved



