A244113 Primes p such that f(p), f(f(p)), f(f(f(p))), and f(f(f(f(p)))) are all prime, where f(x) = x^2+3x+1.

3, 1628779, 2481113, 3260683, 3520229, 9733123, 10671253, 10673129, 11772809, 36758303, 45459353, 45594019, 58552279, 64597903, 66539353, 74674559, 83471243, 96765313, 115623929, 117479039, 131701183, 133500553, 145010533, 163341319, 163845719, 166410353, 167197243, 169948223

Offset: 1

Author

Zak Seidov, Nov 11 2014

Keywords

• nonn

Examples

			p = 3, f(p) = 19,  f(19) = 419, f(419) = 176819 , and  f(176819) = 31265489219 all prime.
		

Crossrefs

Subsequence of A250027. Cf. A094210, A153590.

Programs

Mathematica

Select[Prime[Range[10^7]],AllTrue[Rest[NestList[#^2+3#+1&,#,4]], PrimeQ]&] (* The program uses the AllTrue function from Mathematica version 10 *) (* Harvey P. Dale, Apr 12 2018 *)