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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A330414 Cyclops primes that become a cube when the middle "0" is removed.

Original entry on oeis.org

68059, 1170649, 4560533, 7530571, 136501919, 158103251, 173703979, 212503933, 226605187, 356101289, 362604691, 382702753, 439806977, 518905117, 811802737, 954403993, 19484041249, 19956016979, 22635071297, 24658046551, 27263097773, 34635012697, 35326042667, 37166072149, 39668022287, 41499095543, 44839062449
Offset: 1

Views

Author

Rodolfo Ruiz-Huidobro, Dec 14 2019

Keywords

Examples

			a(1) = 68059 because 6859 = 19^3 is the first cube that results from the removal of the 0 digit from a cyclops prime.
136501919 is a term because 13651919 is 239^3.
		

Crossrefs

Programs

  • Maple
    count:= 0: Res:= NULL:
    for d from 2 to 6 do
      for n from ceil(10^((2*d-1)/3)) to floor((10^(2*d)-1)^(1/3)) do
        L:=convert(n^3,base,10);
        if member(0,L) then next fi;
        a:= n^3 mod 10^d;
        p:= 10*(n^3-a)+a;
        if isprime(p) then
          count:= count+1; Res:= Res, p;
        fi
    od od:
    Res; # Robert Israel, Dec 24 2019
  • PARI
    seq(n)={my(i=0, L=List()); while(#Lt==0,v), my(m=fromdigits(concat([v[1..k], 0, v[k+1..#v]]))); if(isprime(m), listput(L,m)))); Vec(L)} \\ Andrew Howroyd, Dec 20 2019
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