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

1,1

Links

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

Example

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

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 *)

Crossrefs

Cf. A108540.

Sequence in context: A254451 A205929 A145049 * A235218 A235662 A235666

Adjacent sequences: A108703 A108704 A108705 * A108707 A108708 A108709

Keyword

base,nonn

Author

Jason Earls, Jun 20 2005

Extensions

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

Offset corrected by Amiram Eldar, Nov 29 2019

Status

approved