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%I #14 Sep 04 2023 19:57:19
%S 21,93,381,1065,1173,5065,5670,5729,6603,8809,10281,10680,15960,17110,
%T 39286,40526,47882,49951,61962,85058,85261,99066,117860,125985,126853,
%U 135890,143241,159901,171945,179556,185853,208744,209585,210450,251394,261767,288792
%N Numbers k such that sigma(k) and sigma(k+1) are nontrivial powers (A065496).
%e 10680 is in this sequence because sigma(10680)=180^2 and sigma(10681)=108^2. - _Sean A. Irvine_, Sep 04 2023
%t nn = 300000; SequencePosition[Array[GCD @@ FactorInteger[DivisorSigma[1, #]][[All, -1]] &, nn + 1], {_?(# > 1 &), _?(# > 1 &)}][[All, 1]] (* _Michael De Vlieger_, Sep 04 2023 *)
%Y Cf. A065496.
%K nonn
%O 1,1
%A _Robert G. Wilson v_, Nov 27 2001
%E Missing terms inserted by _Sean A. Irvine_, Sep 04 2023
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