login
A165572
Greater prime factor of successively better golden semiprimes.
5
3, 5, 11, 31, 37, 47, 157, 571, 911, 1021, 1487, 2351, 3571, 24709, 25463, 69247, 80803, 216103, 290141, 465277, 822691, 1485373, 1785473, 3206767, 14855327, 27439609, 28075231, 84468479, 107765599, 161223523, 218252393, 788298307, 1018470703, 1527131129, 2472296341
OFFSET
1,1
COMMENTS
See A165569 and A165570 for the definition. Probably a subset of A108542.
LINKS
FORMULA
a(n) = A108539(A165569(n)).
a(n) = A165570(n)/A165571(n).
MATHEMATICA
f[p_] := Module[{x = GoldenRatio * p, p1, p2}, p1 = NextPrime[x, -1]; p2 = NextPrime[p1]; If[p2 - x > x - p1, p1, p2]]; seq={}; dm = 1; p1 = 1; Do[p1 = NextPrime[p1]; k++; p2 = f[p1]; d = Abs[p2/p1 - GoldenRatio]; If[d < dm, dm = d; AppendTo[seq, p2]], {10^4}]; seq (* Amiram Eldar, Nov 28 2019 *)
CROSSREFS
KEYWORD
nonn,more
AUTHOR
Antti Karttunen, Sep 22 2009
EXTENSIONS
a(16)-a(23) from Donovan Johnson, May 13 2010
a(24)-a(35) from Amiram Eldar, Nov 28 2019
STATUS
approved