A102542 Numbers k such that k333333 is prime.

10, 29, 31, 32, 34, 46, 50, 58, 62, 76, 79, 82, 83, 89, 100, 103, 109, 113, 115, 127, 137, 149, 151, 157, 158, 178, 184, 190, 194, 199, 205, 212, 218, 223, 236, 241, 257, 298, 302, 317, 326, 328, 337, 356, 358, 373, 386, 388, 395, 404, 409, 419, 449, 460, 464, 467, 479, 485, 488, 491, 502, 512

Offset

1,1

Links

Table of n, a(n) for n=1..62.

Example

If k =  10, then k333333 =  10333333 (prime);
if k =  58, then k333333 =  58333333 (prime);
if k = 100, then k333333 = 100333333 (prime).

Maple

q:= n-> isprime(parse(cat(n, 3$6))):
select(q, [$1..512])[];  # Alois P. Heinz, Oct 29 2021

Mathematica

Select[Range[550], PrimeQ[FromDigits[Join[IntegerDigits[#], {3, 3, 3, 3, 3, 3}]]]&] (* Harvey P. Dale, Apr 13 2012 *)

Prog

(Magma) [ n: n in [1..700] | IsPrime(Seqint([3, 3, 3, 3, 3, 3] cat Intseq(n))) ]; // Vincenzo Librandi, Feb 04 2011
(PARI) is(n)=isprime(n*10^6+333333) \\ Charles R Greathouse IV, May 15 2013
(Python)
from sympy import isprime
def aupto(limit):
    return [k for k in range(limit+1) if isprime(int(str(k) + "333333"))]
print(aupto(512)) # Michael S. Branicky, Oct 29 2021

Crossrefs

Sequence in context: A066527 A343385 A103423 * A098751 A143190 A009771

Adjacent sequences: A102539 A102540 A102541 * A102543 A102544 A102545

Keyword

base,nonn

Author

Parthasarathy Nambi, Feb 24 2005

Status

approved