%I #8 Jul 09 2022 14:03:03
%S 2,76,782,1836,3996,26754,28896,51240,122598,130734,265524,306204,
%T 379350,450846,735012,1132740,1169472,2120160,2670974,4095080,4312440,
%U 4421088,8448120,8693640,9404160,10113966,10890978,12710304,12945312,15328872,16385376,18028836
%N Sequence lists numbers k > 1 such that k^4 == phi(k) (mod sigma(k)), where phi = A000010 and sigma = A000203.
%F Solutions of k^4 mod sigma(k) = phi(k).
%e sigma(76) = 140 and 76^4 mod 140 = 36 = phi(76).
%p with(numtheory): op(select(n->n^4 mod sigma(n)=phi(n), [$1..2670974]));
%t Select[Range[2,41*10^5],PowerMod[#,4,DivisorSigma[1,#]]==EulerPhi[#]&] (* The program generates the first 20 terms of the sequence. *) (* _Harvey P. Dale_, Jul 09 2022 *)
%Y Cf. A000010, A000203, A324214, A324215.
%K nonn,easy
%O 1,1
%A _Paolo P. Lava_, Feb 18 2019
%E a(23)-a(32) from _Giovanni Resta_, Feb 19 2019