A165444 Primes obtained from other primes by prefixing a 4.

43, 47, 419, 431, 443, 461, 467, 479, 4127, 4139, 4157, 4211, 4229, 4241, 4271, 4283, 4337, 4349, 4373, 4397, 4409, 4421, 4457, 4463, 4523, 4547, 4643, 4673, 4691, 4733, 4751, 4787, 4877, 4919, 4937, 4967, 41039, 41051, 41117, 41201, 41213, 41231, 41381, 41399

Offset: 1

Author

Parthasarathy Nambi, Sep 19 2009

Keywords

• base
• nonn

Examples

			4547 is a prime obtained by prefixing a 4 to the prime 547.
		

Links

• Harvey P. Dale, Table of n, a(n) for n = 1..1000
• Chris Caldwell, The First 10,000 Primes

Crossrefs

Cf. A000040, A165243, A165292

Programs

Mathematica

Select[4*10^IntegerLength[#]+#&/@Prime[Range[300]],PrimeQ] (* Harvey P. Dale, Mar 25 2016 *)

Extensions

More terms from Vincenzo Librandi, Sep 20 2009