cp's OEIS Frontend

A379125 Sum of divisors of those odd squares k for which A379113(k) > 1, i.e., k that have a proper unitary divisor d > 1 such that A048720(A065621(sigma(d)),sigma(k/d)) is equal to sigma(k).

%I A379125 #8 Dec 20 2024 12:35:48
%S A379125 403,4123,4953,18291,46101,73749,133939,400179,291441,542469,618673,
%T A379125 1153633,1119859,1098867,1077699,1599249,2309619,6848721,20421219,
%U A379125 20131059,17598529,17022999,44205381,59669253,80520921,68946969,88131729,83998281,88119813,97595019,102760497,137273157,147291249,211492119,574669953
%N A379125 Sum of divisors of those odd squares k for which A379113(k) > 1, i.e., k that have a proper unitary divisor d > 1 such that A048720(A065621(sigma(d)),sigma(k/d)) is equal to sigma(k).
%H A379125 Antti Karttunen, <a href="/A379125/b379125.txt">Table of n, a(n) for n = 1..2025</a>
%H A379125 <a href="/index/Con#CongruCrossDomain">Index entries for sequences defined by congruent products between domains N and GF(2)[X]</a>.
%H A379125 <a href="/index/Ge#GF2X">Index entries for sequences related to polynomials in ring GF(2)[X]</a>.
%H A379125 <a href="/index/Si#SIGMAN">Index entries for sequences related to sigma(n)</a>.
%F A379125 a(n) = A000203(A379121(n)).
%F A379125 a(n) = A277320(sigma(A379123(n)), sigma(A379124(n))).
%F A379125 a(n) = sigma(A379123(n)) * sigma(A379124(n)).
%o A379125 (PARI) forstep(n=1,oo,2,if(A379113(n^2)>1, k++; print1(sigma(n^2), ", ")));
%Y A379125 Cf. A000203, A048720, A065621, A277320, A379113, A379121, A379123, A379124.
%K A379125 nonn
%O A379125 1,1
%A A379125 _Antti Karttunen_, Dec 18 2024