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 A109806 #10 Sep 22 2019 07:46:48 %S A109806 20,56,104,368,464,650,836,992,1952,8415,11096,16256,17816,28544, %T A109806 31815,45356,77744,83312,91388,98048,113072,122624,128768,130304, %U A109806 254012,351351,388076,507392,522752,537248,698528,780975,791264,1081568 %N A109806 Admirable numbers such that the subtracted divisor is square. %H A109806 Amiram Eldar, <a href="/A109806/b109806.txt">Table of n, a(n) for n = 1..100</a> %e A109806 a(2)=56 because 1+2+7+8+14+28-4 = 56 and the subtracted divisor is square. %t A109806 aQ[n_] := (d = DivisorSigma[1, n] - 2n) > 0 && EvenQ[d] && Mod[n, d/2] == 0 && d < 2n && IntegerQ @ Sqrt[d/2]; Select[Range[10^5], aQ] (* _Amiram Eldar_, Sep 22 2019 *) %Y A109806 Cf. A111592. %K A109806 nonn %O A109806 1,1 %A A109806 _Jason Earls_, Aug 16 2005