A274679 Numbers k such that 7*10^k + 33 is prime.

1, 2, 6, 10, 17, 29, 53, 107, 133, 596, 852, 1068, 1186, 1356, 1673, 1987, 3170, 3312, 5819, 6655, 19267, 20009, 29302, 72614, 170348, 178566

Offset: 1

Author

Vincenzo Librandi, Jul 04 2016

Keywords

• nonn
• more

Examples

			2 is in this sequence because 7*10^2 + 33 = 733 is prime.
4 is not in the sequence because 7*10^4 + 33 = 70033 = 59 * 1187.
Initial terms and associated primes:
a(1) = 1: 103;
a(2) = 2: 733;
a(3) = 6: 7000033;
a(4) = 10: 70000000033, etc.
		

Links

• Makoto Kamada, Search for 70w33.

Crossrefs

Cf. similar sequences listed in A274676.

Programs

Magma

[n: n in [1..500] | IsPrime(7*10^n+33)];

Mathematica

Select[Range[0, 3000], PrimeQ[7 10^# + 33] &]

PARI

lista(nn) = for(n=1, nn, if(ispseudoprime(7*10^n+33), print1(n, ", "))); \\ Altug Alkan, Jul 05 2016

Extensions

a(19)-a(20) from Michael S. Branicky, Aug 16 2021

a(21)-a(26) from Kamada data by Tyler Busby, Apr 14 2024