cp's OEIS Frontend

This is a front-end for the Online Encyclopedia of Integer Sequences, made by Christian Perfect. The idea is to provide OEIS entries in non-ancient HTML, and then to think about how they're presented visually. The source code is on GitHub.

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A320725 Prime numbers such that all other numbers obtained from all permutations of all subsets of the digits are nonprime.

Original entry on oeis.org

2, 3, 5, 7, 11, 19, 41, 61, 89, 409, 449, 499, 881, 6469
Offset: 1

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Author

Daniel Lignon, Oct 19 2018

Keywords

Comments

Sequence is finite since it is a subsequence of a finite sequence (A071062).
This is complete: there are only 14 terms in the sequence.

Examples

			449 is in this sequence because it's prime and none of the numbers 4, 9, 44, 49, 94, 494 and 944 is prime.

Crossrefs

Subsequence of A071062.
Cf. A320726 (the same for composite numbers).

Programs

  • Mathematica
    Select[Prime@ Range[10^3], NoneTrue[DeleteCases[FromDigits /@ Rest@ Union@ Apply[Join, Permutations /@ Subsets@ IntegerDigits@ #], #], PrimeQ] &] (* Michael De Vlieger, Oct 22 2018 *)
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Started in 1964 by Neil J. A. Sloane | Maintained by The OEIS Foundation Inc.

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