login
A107787
Golden semiprimes that are not brilliant numbers.
1
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
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
Sequence in context: A180837 A361112 A210811 * A099638 A046191 A115616
KEYWORD
base,nonn
AUTHOR
Jason Earls, Jun 14 2005
EXTENSIONS
More terms from Donovan Johnson, Mar 06 2008
STATUS
approved