A379114 - OEIS

%I #11 Dec 17 2024 19:52:09

%S 6,10,12,14,15,20,21,22,24,26,28,30,33,35,39,40,42,44,46,48,50,51,52,

%T 55,56,57,58,60,62,63,65,66,69,70,72,75,76,77,78,80,84,86,87,88,91,92,

%U 93,94,96,100,102,104,105,108,111,112,114,115,116,118,119,120,122,123,124,126,129,132,133,136,138,140,141,143,144

%N Numbers 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 Antti Karttunen, <a href="/A379114/b379114.txt">Table of n, a(n) for n = 1..20000</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>.

%o (PARI) is_A379114(n) = (A379113(n)>1);

%Y Positions of terms > 1 in A379113.

%Y Cf. A000396 (subsequence, at least the even terms are), A379118 (characteristic function).

%Y Cf. also A325638, A325639 (not subsequences).

%K nonn

%O 1,1

%A _Antti Karttunen_, Dec 17 2024