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Numbers n such that the number n33 is prime.
4

%I #21 Apr 03 2023 10:36:10

%S 2,4,7,10,14,17,19,23,26,28,34,35,37,38,41,47,49,52,53,61,67,68,73,74,

%T 79,82,89,91,94,95,97,98,101,103,104,107,116,118,119,124,130,136,139,

%U 140,145,146,152,157,160,163,164,166,170,173,181,182,184,193,194,202

%N Numbers n such that the number n33 is prime.

%H Daniel Starodubtsev, <a href="/A101472/b101472.txt">Table of n, a(n) for n = 1..10000</a>

%H Chris Caldwell <a href="https://t5k.org/lists/small/1000.txt">The first 1,000 primes</a>.

%e If n=2, then n33 = 233 (prime);

%e If n=34, then n33 = 3433 (prime);

%e If n=74, then n33 = 7433 (prime).

%t fQ[n_] := PrimeQ[FromDigits[ Join[ IntegerDigits[n], {3, 3}]]]; Select[ Range[203], fQ[ # ] &] (* _Robert G. Wilson v_, Feb 04 2005 *)

%t Select[Range[250], PrimeQ[FromDigits[Flatten[{IntegerDigits[#], IntegerDigits[33]}]]] &] (* _Vincenzo Librandi_, Jul 31 2015 *)

%t Select[Range[210],PrimeQ[100#+33]&] (* _Harvey P. Dale_, Jul 04 2017 *)

%o (Magma) [n: n in [0..250] | IsPrime(Seqint(Intseq(33) cat Intseq(n)))]; // _Vincenzo Librandi_, Jul 31 2015

%o (PARI) is(n)=isprime(100*n+33) \\ _Charles R Greathouse IV_, May 22 2017

%Y Cf. A090263, A109369.

%K nonn,base

%O 1,1

%A _Parthasarathy Nambi_, Jan 30 2005

%E More terms from _Robert G. Wilson v_, Feb 04 2005

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Last modified September 22 13:36 EDT 2024. Contains 376114 sequences. (Running on oeis4.)