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%I #12 May 21 2018 03:22:46
%S 2,3,4,31,37,39,46,77,98,119,124,143,144,154,169,197,205,232,245,266,
%T 291,295,297,305,308,319,332,333,413,426,431,437,454,459,472,483,513,
%U 528,531,542,579,617,619,635,647,677,724,737,748,780,806,815,819,820,840,851,858,870,875,907,920,927,940,983,1002,1028
%N Numbers n such that Phi(40,n) is prime, where Phi is the cyclotomic polynomial.
%H G. C. Greubel, <a href="/A250189/b250189.txt">Table of n, a(n) for n = 1..10000</a>
%t Select[Range[1200], PrimeQ[Cyclotomic[40, #]] &] (* _Vincenzo Librandi_, Jan 16 2015 *)
%o (PARI) {is(n)=isprime(polcyclo(40,n))};
%o for(n=1,1000, if(is(n), print1(n, ", "))) \\ _G. C. Greubel_, May 20 2018
%Y Cf. A246392.
%K nonn
%O 1,1
%A _R. J. Mathar_, Jan 12 2015
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