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A108542 Greater prime factor of n-th golden semiprime. 11
3, 5, 11, 17, 31, 37, 47, 59, 67, 109, 127, 157, 163, 167, 173, 211, 241, 263, 271, 293, 313, 367, 389, 439, 449, 457, 503, 571, 593, 613, 619, 643, 661, 677, 701, 727, 739, 787, 823, 911, 983, 991, 1021, 1069, 1163, 1187, 1231, 1289, 1381, 1429, 1487, 1523 (list; graph; refs; listen; history; text; internal format)
OFFSET
1,1
COMMENTS
abs(phi*A108541(n) - a(n)) < 1, where phi = golden ratio = (1+sqrt(5))/2.
LINKS
FORMULA
a(n) = A108540(n)/A108541(n).
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, AppendTo[seq, q]], {200}]; seq (* Amiram Eldar, Nov 28 2019 *)
CROSSREFS
Subsequence of A108539.
Sequence in context: A309437 A309438 A309439 * A006450 A085918 A267094
KEYWORD
nonn
AUTHOR
Reinhard Zumkeller, Jun 09 2005
STATUS
approved

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Last modified June 20 11:12 EDT 2024. Contains 373527 sequences. (Running on oeis4.)