%I #15 Aug 10 2021 04:53:38
%S 1,11,121,253,737,1331,2783,5819,8107,14641,16951,30613,49379,64009,
%T 89177,116897,133837,161051,186461,336743,389873,543169,640343,704099,
%U 980947,1135717,1285867,1292071,1472207,1771561,2051071,2688631
%N Numbers k that divide 7^k + 4^k.
%t Select[Range[269*10^4],Mod[PowerMod[7,#,#]+PowerMod[4,#,#],#]==0&] (* _Harvey P. Dale_, Jun 25 2021 *)
%Y Cf. A074613.
%K nonn
%O 1,2
%A _David W. Wilson_
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