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

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

1,1

Links

Robert Israel, Table of n, a(n) for n = 1..10000 (first 60 terms from Rodolfo Ruiz-Huidobro)

Example

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.

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

Prog

(PARI) seq(n)={my(i=0, L=List()); while(#L<n, i++; my(v=digits(i^3), k=#v\2); if(#v==2*k && !#select(t->t==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

Crossrefs

Cf. A329737, A134809, A016755.

Sequence in context: A234655 A104948 A237807 * A237389 A234662 A250924

Adjacent sequences: A330411 A330412 A330413 * A330415 A330416 A330417

Keyword

nonn,base,easy

Author

Rodolfo Ruiz-Huidobro, Dec 14 2019

Status

approved