A369003 - OEIS

%I #9 Jan 15 2024 10:03:36

%S 2,3,4,5,6,7,8,10,11,13,14,17,18,19,22,23,24,26,27,29,30,31,32,34,36,

%T 37,38,40,41,42,43,45,46,47,48,50,53,54,56,58,59,60,61,62,63,64,66,67,

%U 70,71,72,73,74,75,78,79,80,82,83,84,86,88,89,90,94,96,97,98,99,100,101,102,103,104,105,106,107,109

%N Numbers k for which k' / gcd(k,k') is odd, where k' stands for the arithmetic derivative of k, A003415.

%o (PARI) isA369003(n) = !A369001(n); \\ See the code in A369001.

%Y Positions of odd terms in A083345. Positions of 0's in A369001.

%Y Cf. A003415, A369002 (complement), A369007 (subsequence).

%Y Cf. also A368999.

%K nonn

%O 1,1

%A _Antti Karttunen_, Jan 14 2024