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%I #11 Feb 24 2024 01:06:27
%S 21,42,63,84,126,147,168,189,252,294,336,378,441,504,567,588,672,756,
%T 882,1008,1029,1134,1176,1323,1344,1512,1701,1764,2016,2058,2268,2352,
%U 2646,2688,3024,3087,3402,3528,3969,4032,4116,4536,4704,5103,5292
%N Numbers k such that the k-th cyclotomic polynomial has exactly 9 nonzero terms.
%F {k : A051664(k) = 9}. - _R. J. Mathar_, Sep 15 2012
%Y Cf. A086779.
%K nonn
%O 1,1
%A Yuval Dekel (dekelyuval(AT)hotmail.com), Aug 05 2003