A321701 Primes that are not base-5 deletable primes (written in base 10).

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

Offset

1,1

Comments

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.

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

Robert Price, Table of n, a(n) for n = 1..31550

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

Cf. A080608, A080603, A096235-A096246, A321657.

Sequence in context: A002584 A001990 A043062 * A243012 A053244 A096696

Adjacent sequences: A321698 A321699 A321700 * A321702 A321703 A321704

Keyword

nonn,base,easy

Author

Robert Price, Nov 17 2018

Status

approved