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.

A352584 Numbers k whose decimal representation contains all distinct prime factors of k as substrings.

Original entry on oeis.org

2, 3, 5, 7, 11, 13, 17, 19, 23, 25, 29, 31, 32, 37, 41, 43, 47, 53, 59, 61, 67, 71, 73, 79, 83, 89, 97, 101, 103, 107, 109, 113, 125, 127, 128, 131, 135, 137, 139, 149, 151, 157, 163, 167, 173, 175, 179, 181, 191, 193, 197, 199, 211, 223, 227, 229, 233, 239, 241, 243, 250
Offset: 1

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Author

Ivan N. Ianakiev, Mar 21 2022

Keywords

Comments

All primes (A000040) and powers of 5 (A000351 without 1) are terms.

Crossrefs

Cf. A000040, A000351, A239058 (divisor substrings).

Programs

  • Mathematica
    str[n_]:=ToString/@First/@FactorInteger[n];
    fQ[n_]:=Union[Table[StringContainsQ[ToString[n],str[n][[i]]],{i,Length[str[n]]}]]=={True}; Select[Range[2,1000],fQ]
    dpfQ[n_]:=Union[SequenceCount[IntegerDigits[n],IntegerDigits[#]]&/@(FactorInteger[n][[;;,1]])] == {1}; Select[Range[2,300],dpfQ] (* Harvey P. Dale, May 30 2023 *)