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 A126163 #10 Feb 16 2025 08:33:04
%S A126163 0,1,8,27,102,375,1134,3589,11942,40410
%N A126163 Number of super unitary amicable pairs (i,j) with i<j and i<=10^n.
%H A126163 Eric Weisstein's World of Mathematics, <a href="https://mathworld.wolfram.com/SuperUnitaryAmicablePair.html">Super unitary amicable pairs</a>
%F A126163 Integer pairs (m,n) with m<n and for which usigma(usigma(m))=usigma(usigma(n))=m+n.
%e A126163 a(6)=375 because there are 375 super unitary (m,n) pairs with m<n and for which m<=10^6
%t A126163 UnitaryDivisors[n_Integer?Positive] := Select[Divisors[n], GCD[ #, n/# ] == 1 \ &];
%t A126163 UnitaryDivisorSum[n_Integer?Positive] := Plus @@ UnitaryDivisors[n];
%t A126163 f[ k_] := Nest[UnitaryDivisorSum, k, 2] - k;
%t A126163 g[ k_] := Nest[UnitaryDivisorSum, f[k], 2] - f[k];
%t A126163 m = 10^7;
%t A126163 data1 = Select[Range[m], g[ # ] == # &];
%t A126163 data2 = Nest[UnitaryDivisorSum, #, 2] - # & /@ data1;
%t A126163 data3 = Table[{data1[[k]], data2[[k]]}, {k, 1, Length[data1]}];
%t A126163 data4 = DeleteCases[Table[If[Nest[UnitaryDivisorSum, First[data3[[k]]], 2] == Nest[UnitaryDivisorSum, Last[data3[[k]]], 2] \ && ! First[data3[[k]]] >= Last[data3[[k]]], data3[[k]], 0], {k, 1, Length[data3]}], 0];
%t A126163 data5 = Table[Length[Select[data4, First[ # ] < 10^k \ &]], {k, 1, 7}]
%Y A126163 Cf. A045613, A045614.
%K A126163 hard,nonn,more
%O A126163 1,3
%A A126163 _Ant King_, Dec 20 2006
%E A126163 a(8)-a(10) from _Amiram Eldar_, Feb 18 2019