cp's OEIS Frontend

A324709 Larger of tri-unitary amicable numbers pair: numbers (m, n) such that tsigma(m) = tsigma(n) = m + n, where tsigma(n) is the sum of the tri-unitary divisors of n (A324706).

%I A324709 #9 Dec 29 2021 05:58:00
%S A324709 126,846,1260,8460,11760,10856,14595,17700,49308,83142,62700,71145,
%T A324709 73962,83904,107550,88730,131100,168730,149952,196650,203432,306612,
%U A324709 365700,399592,419256,548550,721962,669688,831420,686072,691256,712216,652664,661824,827700
%N A324709 Larger of tri-unitary amicable numbers pair: numbers (m, n) such that tsigma(m) = tsigma(n) = m + n, where tsigma(n) is the sum of the tri-unitary divisors of n (A324706).
%C A324709 The terms are ordered according to their lesser counterparts (A324708).
%H A324709 Amiram Eldar, <a href="/A324709/b324709.txt">Table of n, a(n) for n = 1..1000</a>
%e A324709 126 is in the sequence since it is the larger of the amicable pair (114, 126): tsigma(114) = tsigma(126) = 114 + 126.
%t A324709 f[p_, e_] := If[e == 3, (p^4-1)/(p-1), If[e==6, (p^8-1)/(p^2-1), p^e+1]]; tsigma[1]=1; tsigma[n_]:= Times @@ f @@@ FactorInteger[n]; s[n_] := tsigma[n] - n; seq={}; Do[m=s[n]; If[m>n && s[m]==n, AppendTo[seq, m]] ,{n,1,700000}]; seq
%Y A324709 Cf. A002046, A002953, A126170, A292981, A322542, A324706, A324707, A324708.
%K A324709 nonn
%O A324709 1,1
%A A324709 _Amiram Eldar_, Mar 11 2019