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 A281900 #21 Feb 18 2025 02:10:38 %S A281900 1,3,6,7,15,16,34,240,241,317,502,503,504,505,1077,1178,1179,1806, %T A281900 4866,4901,4902,4946,4947,8195,8196,8197,8198,8199,8200,8201,8202, %U A281900 8203,8204,45393,45485,45486,96358,96359,96360,96361,96362,96363,96364,96365,96366 %N A281900 Index of first occurrence of n in A281579, or -1 if n does not appear there.. %C A281900 The sequence is strictly increasing. %C A281900 It is conjectured that every number >= 2 does appear in A281579. %C A281900 a(n) is also the index of the first occurrence of n-1 in A380317, or -1 if n-1 does not appear there. %H A281900 Rémy Sigrist, <a href="/A281900/b281900.txt">Table of n, a(n) for n = 2..1904</a> (a(2)-a(968) added on Feb 01 2017, a(969)-a(1904) added on Feb 06 2017) %H A281900 Rémy Sigrist, <a href="/A281900/a281900.txt">C++ program for A281900</a> %Y A281900 Cf. A281579, A310387. %K A281900 nonn %O A281900 2,2 %A A281900 _Rémy Sigrist_, Feb 01 2017 %E A281900 Escape clause added to definition by _N. J. A. Sloane_, Feb 17 2025