A241488 Primes p such that p+8, p+888 and p+8888 are also prime.

53, 263, 389, 431, 983, 1013, 1061, 1223, 1571, 1823, 2789, 3323, 3533, 3911, 4211, 5849, 6563, 6653, 7019, 7481, 8369, 8963, 9041, 9173, 9413, 9539, 9803, 10091, 10559, 10979, 12611, 12689, 12911, 13163, 13751, 13781, 14243, 14879, 15083, 16691, 17231, 17483

Offset

1,1

Comments

All the terms in the sequence are congruent to 2 mod 3.

The constants in the definition (8, 888 and 8888) are the concatenation of digit 8.

Links

K. D. Bajpai, Table of n, a(n) for n = 1..10000

Example

a(1) = 53 is a prime: 53+8 = 61, 53+888 = 941 and 53+8888 = 8941 are also prime.
a(2) = 263 is a prime: 263+8 = 271, 263+888 = 1151 and 263+8888 = 9151 are also prime.

Maple

KD:= proc() local a, b, d, e; a:= ithprime(n); b:=a+8; d:=a+888; e:=a+8888; if isprime(b)and isprime(d)and isprime(e)  then return (a) :fi; end: seq(KD(), n=1..5000);

Mathematica

KD = {}; Do[p = Prime[n]; If[PrimeQ[p + 8] && PrimeQ[p + 888] && PrimeQ[p + 8888], AppendTo[KD, p]], {n, 5000}]; KD
(*For the b-file*)  c = 0; p = Prime[n]; Do[If[PrimeQ[p + 8] && PrimeQ[p + 888] && PrimeQ[p + 8888], c = c + 1; Print[c, "  ", p]], {n, 1, 5*10^6}];
Select[Prime[Range[2500]], AllTrue[#+{8, 888, 8888}, PrimeQ]&] (* The program uses the AllTrue function from Mathematica version 10 *) (* Harvey P. Dale, Jul 31 2017 *)

Prog

(PARI) s=[]; forprime(p=2, 18000, if(isprime(p+8) && isprime(p+888) && isprime(p+8888), s=concat(s, p))); s \\ Colin Barker, Apr 25 2014

Crossrefs

Cf. A000040, A023200, A046136, A230223, A236302, A236304, A237890, A241485.

Sequence in context: A142061 A107150 A036911 * A140851 A337428 A253119

Adjacent sequences: A241485 A241486 A241487 * A241489 A241490 A241491

Keyword

nonn

Author

K. D. Bajpai, Apr 23 2014

Status

approved