A369656 - OEIS

A369656

Numbers k such that k' is odd and also k'' is odd, where k' stands for the arithmetic derivative of k, A003415(k).

%I #5 Feb 05 2024 18:07:33

%S 6,10,22,27,30,34,42,50,58,66,70,78,82,86,99,105,114,118,122,125,126,

%T 130,142,146,154,165,174,182,194,202,206,207,214,222,230,231,238,242,

%U 243,246,250,255,273,274,279,282,285,286,298,302,310,318,326,333,343,345,346,357,358,366,369,370,374,382,385,386

%N Numbers k such that k' is odd and also k'' is odd, where k' stands for the arithmetic derivative of k, A003415(k).

%C Numbers k that are in A235991 and also A003415(k) is in A235991.

%o (PARI) \\ See A369655.

%Y Cf. A000035, A003415, A068346, A235991, A351228, A369655 (characteristic function).

%K nonn

%O 1,1

%A _Antti Karttunen_, Feb 05 2024