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 A338380 #37 Nov 15 2020 12:26:53 %S A338380 1,2,3,5,7,10,13,18,23,16,9,19,29,42,55,73,91,68,45,61,77,86,95,114, %T A338380 133,104,75,117,159,214,269,342,415,324,233,165,97,142,187,248,309, %U A338380 232,155,241,327,422,517,631,745,612,479,375,271,196,121,238,355,514,673,887,1101,832,563,905,1247,1662,2077 %N A338380 Replace every term a(n) by the pair [a(n), a(n)] to form a new sequence S: S is the succession of the absolute differences of the starting sequence. %C A338380 This is the lexicographically earliest sequence of distinct positive terms with this property. %H A338380 Carole Dubois, <a href="/A338380/b338380.txt">Table of n, a(n) for n = 1..5001</a> %e A338380 The successive absolute differences between two successive terms are 1, 1, 2, 2, 3, 3, 5, 5, 7, 7, 10, 10, 13, 13, 18, 18, 23, 23, 16, 16, 9, 9,... which is the sequence itself with every term duplicated. %Y A338380 Cf. A033485 (same sequence, but strictly monotonically increasing). %K A338380 base,nonn %O A338380 1,2 %A A338380 _Eric Angelini_ and _Carole Dubois_, Nov 05 2020