A108706 Reverse these primes to get golden semiprimes.

3037, 3631, 10271, 92251, 334651, 3302191, 3349403, 3494923, 3500897, 3574297, 3971207, 9067837, 9150139, 11914451, 16077421, 16651111, 30842221, 32333971, 34747217, 71704051, 71900987, 76642031, 78818581, 92032757, 104062963

Offset: 1

Author

Jason Earls, Jun 20 2005

Keywords

• base
• nonn

Examples

			The prime 3631 is in the sequence because reversed it is 1363 = 29*47 and abs(29*phi-47) = 0.077014... < 1.
		

Links

• Amiram Eldar, Table of n, a(n) for n = 1..336 (terms below 10^11)

Crossrefs

Cf. A108540.

Programs

Mathematica

revDigits[n_] := FromDigits @ Reverse @ IntegerDigits[n]; goldQ[n_] := Module[{f = FactorInteger[n]}, If[Length[f] != 2, False, If[Max[f[[;;,2]]] != 1, False, Abs[f[[2,1]] - f[[1,1]] * GoldenRatio] < 1]]]; seqQ[n_] := PrimeQ[n] && goldQ @ revDigits[n]; Select[Range[4*10^6], seqQ] (* Amiram Eldar, Nov 29 2019 *)

Extensions

a(19)-a(25) from Donovan Johnson, Nov 11 2008

Offset corrected by Amiram Eldar, Nov 29 2019