cp's OEIS Frontend

A373265 Numbers k such that k' / gcd(k,k') is of the form 4m+2, where k' stands for the arithmetic derivative of k, A003415.

%I A373265 #6 Jun 01 2024 12:05:14
%S A373265 9,16,20,21,25,33,49,52,57,65,68,69,77,85,93,108,116,121,129,133,135,
%T A373265 141,145,148,161,164,169,177,185,192,201,205,209,212,213,217,221,237,
%U A373265 240,244,249,252,253,265,289,292,300,301,305,309,315,321,329,341,351,356,361,365,375,377,381,388,393,396,404,413,417
%N A373265 Numbers k such that k' / gcd(k,k') is of the form 4m+2, where k' stands for the arithmetic derivative of k, A003415.
%H A373265 Antti Karttunen, <a href="/A373265/b373265.txt">Table of n, a(n) for n = 1..10000</a>
%o A373265 (PARI) isA373265 = A373264;
%Y A373265 Setwise difference A369002 \ A369005.
%Y A373265 Cf. A003415, A083345, A373264 (characteristic function).
%K A373265 nonn
%O A373265 1,1
%A A373265 _Antti Karttunen_, Jun 01 2024