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%I #22 Sep 08 2022 08:44:40
%S 1,2,3,10,12,14,15,16,18,21,26,30,35,39,42,44,54,65,75,76,90,108,123,
%T 126,153,156,165,218,234,252,270,364,366,370,396,462,474,494,508,525,
%U 540,558,615,620,630,646,702,732,814,852,858,918,980,1022,1044
%N Numbers k such that phi(k) | sigma(k + 12).
%H G. C. Greubel, <a href="/A015859/b015859.txt">Table of n, a(n) for n = 1..500</a>
%t Select[Range[1100],Divisible[DivisorSigma[1,#+12],EulerPhi[#]]&] (* _Harvey P. Dale_, Jun 01 2018 *)
%o (PARI) is(n)=!(sigma(n+12)%eulerphi(n)) \\ _Charles R Greathouse IV_, Sep 25 2012
%o (Magma) [n: n in [1..900] | DivisorSigma(1,n+12) mod EulerPhi(n) eq 0]; // _G. C. Greubel_, Dec 13 2018
%Y Cf. A015834 (m=1), A015837 (m=2), A015840 (m=3), A015841 (m=4), A015843 (m=5), A015844 (m=6), A015845 (m=7), A015851 (m=8), A015853 (m=9), A015856 (m=10), A015858 (m=11), this sequence (m=12), A015860 (m=13).
%K nonn
%O 1,2
%A _Robert G. Wilson v_
%E Missing a(1)=1 inserted by _Sean A. Irvine_, Dec 13 2018
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