A379122 - OEIS

A379122

Odd numbers m for which A379113(m^2) > 1, i.e., k = m^2 has a proper unitary divisor d > 1 such that A048720(A065621(sigma(d)),sigma(k/d)) is equal to sigma(k).

%I #9 Dec 20 2024 12:35:05

%S 15,55,57,111,171,195,303,465,497,595,639,867,879,925,959,1169,1263,

%T 1953,3135,3345,3489,3565,5425,6923,7239,8153,8215,8801,8959,9703,

%U 10033,10507,11249,14291,16275,18135,18569,18693,19173,20271,23943,24303,26607,28325,32581,33655,34163,40393,43927,46221,47649,55281

%N Odd numbers m for which A379113(m^2) > 1, i.e., k = m^2 has a proper unitary divisor d > 1 such that A048720(A065621(sigma(d)),sigma(k/d)) is equal to sigma(k).

%H Antti Karttunen, <a href="/A379122/b379122.txt">Table of n, a(n) for n = 1..2025</a>

%H <a href="/index/Con#CongruCrossDomain">Index entries for sequences defined by congruent products between domains N and GF(2)[X]</a>.

%H <a href="/index/Ge#GF2X">Index entries for sequences related to polynomials in ring GF(2)[X]</a>.

%H <a href="/index/Si#SIGMAN">Index entries for sequences related to sigma(n)</a>.

%F {Odd k such that A379113(k^2) > 1}.

%F a(n) = A000196(A379121(n)).

%o (PARI) is_A379122(n) = (n%2 && A379113(n^2)>1);

%Y Square roots of A379121.

%Y Cf. A379113.

%K nonn

%O 1,1

%A _Antti Karttunen_, Dec 18 2024