Year-end appeal: Please make a donation to the OEIS Foundation to support ongoing development and maintenance of the OEIS. We are now in our 61st year, we have over 378,000 sequences, and we’ve reached 11,000 citations (which often say “discovered thanks to the OEIS”).
%I #22 Dec 23 2019 18:56:59
%S 1,3,321,3572225067,44308057022098435739157981016569
%N Integer values of Lucas number A000032(n)/n.
%C The digital root of this sequence appears to be alternately 3 and 6, aside from the initial term of "1".
%C A subsequence of A181885. For instance, a(2)=A181885(6), a(3)=A181885(18), a(4)=A181885(54); a(5)=A181885(162); and, a(6)=A181885(486). Also 6, 18, 54, 162 and 486 are consecutive terms of the Pinot sequence A008776. Is this a coincidence?
%H Andrew Howroyd, <a href="/A272318/b272318.txt">Table of n, a(n) for n = 1..9</a>
%F a(n) = A000032(A016089(n))/n. - _Michel Marcus_, Apr 25 2016
%t LucasL[#]/# & /@ Range@ 1200 /. _Rational -> Nothing (* Version 10.2, or *)
%t Select[Array[LucasL[#]/# &, {1200}], IntegerQ] (* _Michael De Vlieger_, Apr 25 2016 *)
%Y Cf. A000032, A008776, A016089, A167745, A181885, A167745 and A016089.
%K nonn
%O 1,2
%A _Peter M. Chema_, Apr 25 2016