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!)
A321596 Primes that are not Base-2 deletable primes (written in base 10). 1
17, 31, 41, 67, 71, 89, 97, 103, 113, 127, 131, 139, 181, 191, 193, 199, 223, 227, 233, 239, 241, 251, 257, 263, 269, 271, 283, 337, 353, 367, 373, 379, 383, 401, 409, 431, 433, 439, 443, 449, 463, 479, 487, 491, 499, 503, 509, 521, 523, 541, 547, 571, 577 (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. However, in base 2 we adopt the convention that 2 = 10 and 3 = 11 are deletable.

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 A096246.

LINKS

Robert Price, Table of n, a(n) for n = 1..2351

MATHEMATICA

d = {2, 3};

For[n = 3, n <= 15, n++,

  p = Select[Range[2^(n - 1), 2^n - 1], PrimeQ[#] &];

  For[i = 1, i <= Length[p], i++,

   c = IntegerDigits[p[[i]], 2];

   For[j = 1, j <= n, j++,

    t = Delete[c, j];

    If[t[[1]] == 0, Continue[]];

    If[MemberQ[d, FromDigits[t, 2]], AppendTo[d, p[[i]]];  Break[]]]]]; Complement[Table[Prime[n], {n, PrimePi[Last[d]]}], d]

CROSSREFS

Cf. A080608, A080603, A096235-A096246.

Sequence in context: A062579 A134076 A258029 * A160961 A260805 A267781

Adjacent sequences:  A321593 A321594 A321595 * A321597 A321598 A321599

KEYWORD

nonn,base,easy

AUTHOR

Robert Price, Nov 14 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 August 9 22:52 EDT 2020. Contains 336335 sequences. (Running on oeis4.)