A157468 Primes of the form sqrt(p-1)-1, where p is a prime.

3, 5, 13, 19, 23, 53, 73, 83, 89, 109, 149, 179, 223, 229, 239, 263, 269, 283, 313, 349, 383, 419, 439, 443, 463, 569, 593, 643, 653, 673, 739, 859, 863, 919, 929, 1009, 1069, 1093, 1123, 1289, 1319, 1373, 1409, 1429, 1433, 1439, 1459

Offset: 1

Author

Vladimir Joseph Stephan Orlovsky, Mar 01 2009

Keywords

• nonn

Examples

			3 is in the sequence because 3 = sqrt(17 - 1) - 1, where 17 is prime.
5 is in the sequence because 5 = sqrt(37 - 1) - 1, where 37 is prime.
		

Links

• Alois P. Heinz, Table of n, a(n) for n = 1..10000

Crossrefs

Cf. A070155, A127435, A127436, A157467.

Column k=1 of A238048 and A238086.

Programs

Mathematica

Select[Sqrt[#-1]-1&/@Prime[Range[200000]],PrimeQ]  (* Harvey P. Dale, May 19 2012 *)