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 A274333 Indices of Lucas numbers having exactly one primitive prime factor. 2
 0, 2, 4, 5, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 24, 26, 27, 28, 30, 31, 33, 36, 37, 38, 41, 47, 49, 53, 54, 56, 61, 62, 66, 68, 70, 71, 72, 76, 78, 79, 80, 86, 90, 91, 96, 110, 113, 117, 120, 121, 136, 140, 144, 164, 168, 172, 178, 202, 203 (list; graph; refs; listen; history; text; internal format)
 OFFSET 1,2 COMMENTS 0 together with numbers n such that A086600(n) = 1, except if n = 3. The only primes in this sequence are the primes numbers in A001606, which gives the indices of prime Lucas numbers. LINKS Arkadiusz Wesolowski, Table of n, a(n) for n = 1..102 PROG (Magma) lst:=[]; pr:=1; for n in [0..203] do pd:=PrimeDivisors(Lucas(n)); d:=1; t:=0; for c in [1..#pd] do f:=pd[c]; if Gcd(pr, f) eq 1 then t+:=1; else d:=d*f; end if; end for; if t eq 1 then Append(~lst, n); end if; pr:=pr*Truncate(Lucas(n)/d); end for; lst; CROSSREFS Cf. A000032, A001606, A058036, A086600. Sequence in context: A023962 A094562 A178344 * A039241 A000394 A039184 Adjacent sequences: A274330 A274331 A274332 * A274334 A274335 A274336 KEYWORD nonn AUTHOR Arkadiusz Wesolowski, Jun 22 2016 STATUS approved

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Last modified September 18 15:14 EDT 2024. Contains 376000 sequences. (Running on oeis4.)