A107787 Golden semiprimes that are not brilliant numbers.

77, 7303, 10033, 15229, 644251, 706609, 836197, 870071, 936791, 1027333, 1177993, 1261807, 1366553, 1433143, 1525441, 1608161, 62259511, 62782091, 63462979, 64441621, 64973261, 65427751, 65599201, 65837659, 66043093, 66834373, 67966247, 70635437, 70882871

Offset

1,1

Links

Amiram Eldar, Table of n, a(n) for n = 1..10000

Example

7303=67*109 is in the sequence because abs(67*phi-109) = 0.59172... < 1 and its prime factors have an unequal number of decimal digits.

Mathematica

f[p_] := Module[{x = GoldenRatio * p}, p1 = NextPrime[x, -1]; p2 = NextPrime[p1]; q = If[x - p1 < p2 - x, p1, p2]; If[Abs[q - x] < 1, q, 0]]; seq = {}; p = 1; Do[p = NextPrime[p]; q = f[p]; If[q > 0 && IntegerLength[p] != IntegerLength[q], AppendTo[seq, p*q]], {1000}]; seq (* Amiram Eldar, Nov 29 2019 *)

Crossrefs

Cf. A108540, A078972.

Sequence in context: A180837 A361112 A210811 * A099638 A046191 A115616

Adjacent sequences: A107784 A107785 A107786 * A107788 A107789 A107790

Keyword

base,nonn

Author

Jason Earls, Jun 14 2005

Extensions

More terms from Donovan Johnson, Mar 06 2008

Status

approved