This is a front-end for the Online Encyclopedia of Integer Sequences, made by Christian Perfect. The idea is to provide OEIS entries in non-ancient HTML, and then to think about how they're presented visually. The source code is on GitHub.
%I A140198 #8 Sep 12 2019 11:54:39 %S A140198 18,100,1210,2028,6498,23548,49284,146068,201898,223260,296274,564898, %T A140198 1020100,1213594,2230930,2666298,3285748,4304178,5147788,5703298, %U A140198 5896980,7606564,9349410,11645554,19392748,25067908,31754524,41661514,42386748,51755988,54296298 %N A140198 A002326((k-1)/2) for composite numbers k from A141229. %t A140198 r[n_] := EulerPhi[n]/MultiplicativeOrder[2, n]; d[n_] := DivisorSum[n, r[#] &]; f[n_] := (m = MultiplicativeOrder[2, n])*d[n] - m + 1; MultiplicativeOrder[2, #] & /@ Select[Range[10^5], CompositeQ[#] && Total@(r /@ Divisors[#]) - 1 == 3 &] (* _Amiram Eldar_, Sep 12 2019 *) %Y A140198 Cf. A002326, A141229, A001122, A006694. %K A140198 nonn %O A140198 1,1 %A A140198 _Vladimir Shevelev_, Jun 15 2008 %E A140198 a(4) corrected and more terms added by _Amiram Eldar_, Sep 12 2019