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 A033161 #12 Jul 08 2025 19:42:55 %S A033161 2,5,6,9,11,14,15,18,29,32,33,36,38,41,42,45,83,86,87,90,92,95,96,99, %T A033161 110,113,114,117,119,122,123,126,245,248,249,252,254,257,258,261,272, %U A033161 275,276,279,281,284,285,288,326,329,330,333,335,338,339,342,353,356,357,360,362 %N A033161 Begins with (2, 5); avoids 3-term arithmetic progressions. %D A033161 Iacobescu, F. 'Smarandache Partition Type and Other Sequences.' Bull. Pure Appl. Sci. 16E, 237-240, 1997. %D A033161 H. Ibstedt, A Few Smarandache Sequences, Smarandache Notions Journal, Vol. 8, No. 1-2-3, 1997, 170-183. %H A033161 Eric Weisstein's World of Mathematics, <a href="https://mathworld.wolfram.com/NonarithmeticProgressionSequence.html">Nonarithmetic Progression Sequence</a> %Y A033161 a(n) = A033157(n)+1 %K A033161 nonn %O A033161 1,1 %A A033161 _N. J. A. Sloane_