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%I #8 Jun 01 2024 08:15:18
%S 6,15,16,24,28,32,33,40,42,49,51,52,56,60,69,70,76,78,80,87,88,91,96,
%T 98,100,104,105,114,123,124,130,132,133,136,140,141,148,150,152,154,
%U 159,168,169,172,175,176,177,182,184,186,190,195,200,204,213,217,220,222,231,232,238,240,244,245,247,248,249,250,258
%N Numbers k for which A003415(k) == -1 (mod 3), where A003415 is the arithmetic derivative.
%o (PARI) isA373257 = A373256;
%Y Cf. A003415, A373256 (characteristic function).
%Y Positions of -1's in A373253.
%Y Nonnegative integers are partitioned between A327863, A373255, and this sequence.
%K nonn
%O 1,1
%A _Antti Karttunen_, Jun 01 2024