A321658 Primes that are not base-4 deletable primes (written in base 10).

5, 17, 37, 41, 73, 89, 97, 101, 131, 137, 149, 193, 199, 233, 257, 277, 281, 293, 313, 337, 347, 349, 353, 367, 373, 379, 389, 401, 409, 421, 521, 569, 577, 593, 601, 613, 617, 641, 661, 673, 677, 683, 761, 769, 809, 811, 823, 829, 853, 857, 859, 929, 937

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 A319596.

Links

Robert Price, Table of n, a(n) for n = 1..3741

Mathematica

b = 4; 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: A121325 A256970 A145689 * A080167 A060245 A119456

Adjacent sequences: A321655 A321656 A321657 * A321659 A321660 A321661

Keyword

nonn,base,easy

Author

Robert Price, Nov 15 2018

Status

approved