This is a front-end for the Online Encyclopedia of Integer Sequences, made by Christian Perfect. The idea is to provide OEIS entries in non-ancient HTML, and then to think about how they're presented visually. The source code is on GitHub.
%I A373257 #8 Jun 01 2024 08:15:18 %S A373257 6,15,16,24,28,32,33,40,42,49,51,52,56,60,69,70,76,78,80,87,88,91,96, %T A373257 98,100,104,105,114,123,124,130,132,133,136,140,141,148,150,152,154, %U A373257 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 A373257 Numbers k for which A003415(k) == -1 (mod 3), where A003415 is the arithmetic derivative. %o A373257 (PARI) isA373257 = A373256; %Y A373257 Cf. A003415, A373256 (characteristic function). %Y A373257 Positions of -1's in A373253. %Y A373257 Nonnegative integers are partitioned between A327863, A373255, and this sequence. %K A373257 nonn %O A373257 1,1 %A A373257 _Antti Karttunen_, Jun 01 2024