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 A333949 #9 Apr 14 2020 04:19:38 %S A333949 14,206,957,1334,1364,1485,1634,2685,2974,4136,4364,14841,20145,24957, %T A333949 33998,36566,42818,64672,74918,79826,79833,84134,86343,92685,109864, %U A333949 111506,122073,138237,147454,159711,162602,166934,187863,190773,193893,201597,274533,288765 %N A333949 Numbers k such that s(k) = s(k+1), where s(k) is the sum of recursive divisors of k (A333926). %H A333949 Amiram Eldar, <a href="/A333949/b333949.txt">Table of n, a(n) for n = 1..1000</a> %e A333949 14 is a term since A333926(14) = A333926(15) = 24. %t A333949 recDivQ[n_, 1] = True; recDivQ[n_, d_] := recDivQ[n, d] = Divisible[n, d] && AllTrue[FactorInteger[d], recDivQ[IntegerExponent[n, First[#]], Last[#]] &]; recDivs[n_] := Select[Divisors[n], recDivQ[n, #] &]; f[p_, e_] := 1 + Total[p^recDivs[e]]; recDivSum[1] = 1; recDivSum[n_] := Times @@ (f @@@ FactorInteger[n]); Select[Range[10^5], recDivSum[#] == recDivSum[# + 1] &] %Y A333949 Cf. A333926. %Y A333949 Analogous sequences: A002961, A064115 (nonunitary), A064125 (unitary), A293183 (bi-unitary), A306985 (infinitary). %K A333949 nonn %O A333949 1,1 %A A333949 _Amiram Eldar_, Apr 11 2020