login
The OEIS Foundation is supported by donations from users of the OEIS and by a grant from the Simons Foundation.

 

Logo


Hints
(Greetings from The On-Line Encyclopedia of Integer Sequences!)
A321701 Primes that are not base-5 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 (list; graph; refs; listen; history; text; internal format)
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

Lookup | Welcome | Wiki | Register | Music | Plot 2 | Demos | Index | Browse | More | WebCam
Contribute new seq. or comment | Format | Style Sheet | Transforms | Superseeker | Recent
The OEIS Community | Maintained by The OEIS Foundation Inc.

License Agreements, Terms of Use, Privacy Policy. .

Last modified March 28 11:00 EDT 2020. Contains 333083 sequences. (Running on oeis4.)