A321700 Base-5 deletable primes (written in base 10).

2, 3, 7, 11, 13, 17, 19, 23, 37, 47, 53, 59, 61, 67, 71, 73, 79, 89, 97, 103, 107, 113, 137, 197, 227, 239, 263, 269, 271, 307, 311, 317, 337, 347, 353, 359, 367, 373, 379, 389, 397, 439, 449, 479, 487, 503, 523, 547, 557, 563, 569, 571, 607, 613, 677, 727, 739, 887, 947, 977

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.

Links

Robert Price, Table of n, a(n) for n = 1..1511

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[]]]];
d (* Robert Price, Dec 06 2018 *)

Crossrefs

Cf. A080608, A080603, A096235-A096246.

Sequence in context: A181173 A216277 A089174 * A020636 A141657 A265760

Adjacent sequences: A321697 A321698 A321699 * A321701 A321702 A321703

Keyword

nonn,base,easy

Author

Robert Price, Nov 17 2018

Status

approved