A322471 Base-9 deletable primes (written in base 10).

2, 3, 5, 7, 11, 19, 23, 29, 31, 41, 43, 47, 53, 59, 61, 67, 71, 79, 83, 101, 103, 107, 137, 163, 167, 173, 179, 181, 191, 193, 199, 211, 223, 229, 233, 239, 241, 263, 269, 281, 283, 317, 331, 347, 349, 353, 367, 373, 383, 389, 401, 431, 443, 449, 461, 467, 479, 491, 509, 547, 557, 563

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..327

Mathematica

b = 9; 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 09 2018 *)

Crossrefs

Cf. A080608, A080603, A096235-A096246.

Sequence in context: A347337 A210186 A120628 * A262837 A143260 A246044

Adjacent sequences: A322468 A322469 A322470 * A322472 A322473 A322474

Keyword

nonn,base,easy

Author

Robert Price, Dec 09 2018

Status

approved