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 A073083 #21 Sep 08 2022 08:45:06 %S A073083 1,10,12,24,615,4066,7960,30432,49260,133686,440286,1201644,6640812, %T A073083 126953125,411106256,1046704882,11046706752,44588839041 %N A073083 Numbers n such that sum k/d(k) is an integer, where d(k) is the k-th divisor of n (the divisors of n are in decreasing order). %C A073083 a(12) > 11*10^5. - _Emeric Deutsch_, Mar 05 2005 %C A073083 8*10^11 < a(19) <= 2343594361433 = 13^10*17. It seems that the numbers 5^(13*k-3)*13 and 13^(17*k-7)*17, for k > 0, are terms. - _Giovanni Resta_, Dec 06 2019 %e A073083 The divisors of 615 are [615,205,123,41,15,5,3,1] and 1/615+2/205+3/123+4/41+5/15+6/5+7/3+8/1 = 12 is an integer hence 615 is in the sequence. %t A073083 Select[Range[441000],IntegerQ[Total[Range[DivisorSigma[0,#]]/ Reverse[ Divisors[ #]]]]&] (* _Harvey P. Dale_, May 23 2019 *) %o A073083 (Magma) [k:k in [1..500000]|IsIntegral(&+[m/Reverse(Divisors(k))[m]:m in [1..#Divisors(k)]])]; // _Marius A. Burtea_, Dec 06 2019 %Y A073083 Cf. A056538, A073082. %K A073083 nonn,more %O A073083 1,2 %A A073083 _Benoit Cloitre_, Aug 17 2002 %E A073083 More terms from _Emeric Deutsch_, Mar 05 2005 %E A073083 a(12)-a(17) from Lambert Klasen (lambert.klasen(AT)gmx.net), Jul 15 2005 %E A073083 a(18) from _Giovanni Resta_, Dec 06 2019