A102611 Numbers n such that the number n77 is prime.

2, 5, 6, 8, 9, 12, 17, 18, 23, 24, 26, 27, 36, 38, 41, 48, 50, 54, 62, 65, 69, 71, 74, 75, 78, 83, 86, 92, 93, 96, 101, 104, 111, 116, 117, 122, 123, 125, 131, 134, 135, 138, 141, 150, 152, 153, 158, 164, 170, 173, 174, 179, 180, 194, 195, 197, 201, 204, 212, 213, 215

Offset: 1

Author

Parthasarathy Nambi, Jan 30 2005

Keywords

• nonn
• base

Examples

			At n=2, n77 = 277 (prime).
At n=27, n77 = 2777 (prime).
At n=78, n77 = 7877 (prime).
		

Links

• Harvey P. Dale, Table of n, a(n) for n = 1..1000
• Chris Caldwell, The first 1,000 primes.

Programs

Mathematica

fQ[n_] := PrimeQ[ FromDigits[ Join[ IntegerDigits[n], {7, 7}]]]; Select[ Range[218], fQ[ # ] &] (* Robert G. Wilson v, Feb 04 2005 *)
Select[Range[300],PrimeQ[100#+77]&] (* Harvey P. Dale, Mar 17 2015 *)

PARI

is(n)=isprime(100*n+77) \\ Charles R Greathouse IV, Jun 06 2017

Extensions

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