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.

A199325 Primes having only {0, 1, 5} as digits.

Original entry on oeis.org

5, 11, 101, 151, 1051, 1151, 1511, 5011, 5051, 5101, 5501, 10111, 10151, 10501, 11551, 15101, 15511, 15551, 50051, 50101, 50111, 50551, 51001, 51151, 51511, 51551, 55001, 55051, 55501, 55511, 100151, 100501, 100511, 101051, 101111, 101501, 110051, 110501, 115001, 115151, 150001, 150011, 150151, 150551
Offset: 1

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Author

M. F. Hasler, Nov 05 2011

Keywords

Crossrefs

Programs

  • Magma
    [p: p in PrimesUpTo(160000) | Set(Intseq(p)) subset [0, 1, 5]]; // Vincenzo Librandi, Apr 22 2014
  • Maple
    N:= 10000: # to get the first N terms
    count:= 0:
    allowed:= {0,1,5}:
    nallowed:= nops(allowed):
    subst:= seq(i=allowed[i+1],i=0..nallowed-1):
    for d from 0 while count < N do
      for x1 from 1 to nallowed-1 while count < N do
        for t from 0 to nallowed^d-1 while count < N do
          L:= subs(subst,convert(x1*nallowed^d+t,base,nallowed));
          X:= add(L[i]*10^(i-1),i=1..d+1);
          if isprime(X) then
              count:= count+1;
              A[count]:= X;
          fi
    od od od:
    seq(A[n],n=1..N); # Robert Israel, Apr 20 2014
  • Mathematica
    Select[FromDigits/@Tuples[{0,1,5},6],PrimeQ] (* Harvey P. Dale, Jul 23 2021 *)
  • PARI
    L=[0,1,5];for(d=1,6,u=vector(d,i,10^(d-i))~;forvec(v=vector(d,i,[1+(i==1 & !L[1]),#L]),ispseudoprime(t=vector(d,i,L[v[i]])*u)&print1(t",")))  /* see A199327 for a function a(n) */