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.

A190222 Noncomposite numbers all of whose decimal digits are noncomposite numbers (1,2,3,5,7).

This page as a plain text file.
%I A190222 #20 Apr 03 2023 10:36:12
%S A190222 1,2,3,5,7,11,13,17,23,31,37,53,71,73,113,127,131,137,151,157,173,211,
%T A190222 223,227,233,251,257,271,277,311,313,317,331,337,353,373,521,523,557,
%U A190222 571,577,727,733,751,757,773,1117,1123,1151,1153,1171,1213,1217,1223
%N A190222 Noncomposite numbers all of whose decimal digits are noncomposite numbers (1,2,3,5,7).
%H A190222 G. C. Greubel, <a href="/A190222/b190222.txt">Table of n, a(n) for n = 1..1000</a>
%H A190222 Chris Caldwell, The Prime Glossary, <a href="https://t5k.org/glossary/xpage/UnholeyPrime.html">Unholey prime</a>
%F A190222 a(n) >> n^k where k = log(10)/log(5) = 1.43067.... - _Charles R Greathouse IV_, Dec 28 2017
%t A190222 Join[{1}, Select[Range[2000], PrimeQ[#] && Intersection[{0, 4, 6, 8, 9}, IntegerDigits[#]] == {} &]] (* _T. D. Noe_, May 09 2011 *)
%o A190222 (Magma) [1] cat [n: n in PrimesUpTo(1223) | Set(Intseq(n)) subset [1, 2, 3, 5, 7]]; // _Arkadiusz Wesolowski_, Apr 16 2014
%o A190222 (PARI) is(k) = if(!isprime(k) && k != 1, return(0)); setminus(vecsort(digits(k), , 8), [1, 2, 3, 5, 7]) == [] \\ _Iain Fox_, Dec 28 2017
%o A190222 (PARI) is(n) = if(isprime(n), #setminus(Set(digits(k)), [1,2,3,5,7])==0, n==1) \\ _Charles R Greathouse IV_, Dec 28 2017
%Y A190222 Subsequence of A001742.
%K A190222 nonn,base
%O A190222 1,2
%A A190222 _Jaroslav Krizek_, May 06 2011