A101472 Numbers k such that the number k33 is prime.

2, 4, 7, 10, 14, 17, 19, 23, 26, 28, 34, 35, 37, 38, 41, 47, 49, 52, 53, 61, 67, 68, 73, 74, 79, 82, 89, 91, 94, 95, 97, 98, 101, 103, 104, 107, 116, 118, 119, 124, 130, 136, 139, 140, 145, 146, 152, 157, 160, 163, 164, 166, 170, 173, 181, 182, 184, 193, 194, 202

Offset: 1

Author

Parthasarathy Nambi, Jan 30 2005

Keywords

• nonn
• base

Examples

			If k=2,  then k33 =  233 (prime);
If k=34, then k33 = 3433 (prime);
If k=74, then k33 = 7433 (prime).
		

Links

• Daniel Starodubtsev, Table of n, a(n) for n = 1..10000
• Chris Caldwell The first 1,000 primes.

Crossrefs

Cf. A090263, A109369.

Programs

Magma

[n: n in [0..250] | IsPrime(Seqint(Intseq(33) cat Intseq(n)))]; // Vincenzo Librandi, Jul 31 2015

Mathematica

fQ[n_] := PrimeQ[FromDigits[ Join[ IntegerDigits[n], {3, 3}]]]; Select[ Range[203], fQ[ # ] &] (* Robert G. Wilson v, Feb 04 2005 *)
Select[Range[250], PrimeQ[FromDigits[Flatten[{IntegerDigits[#], IntegerDigits[33]}]]] &] (* Vincenzo Librandi, Jul 31 2015 *)
Select[Range[210],PrimeQ[100#+33]&] (* Harvey P. Dale, Jul 04 2017 *)

PARI

is(n)=isprime(100*n+33) \\ Charles R Greathouse IV, May 22 2017

Extensions

More terms from Robert G. Wilson v, Feb 04 2005