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 A049781 #16 Feb 16 2025 08:32:40 %S A049781 1,2,4,5,7,8,11,13,16,17,19,22,25,26,32,34,35,37,38,40,44,47,50,53,56, %T A049781 58,64,65,67,68,71,76,80,82,85,86,95,97,98,101,103,106,110,112,116, %U A049781 118,119,121,130,131,134,137,142,143,145,149,152 %N A049781 a(n) = (b(n) + 1)/2, where b = A000959 (the lucky numbers). %H A049781 Amiram Eldar, <a href="/A049781/b049781.txt">Table of n, a(n) for n = 1..10000</a> %H A049781 R. K. Guy, <a href="https://doi.org/10.1007/978-0-387-26677-0_3">Unsolved Problems in Number Theory</a>, Springer, 2004, C3, pp. 164-165. %H A049781 Eric Weisstein's World of Mathematics, <a href="https://mathworld.wolfram.com/LuckyNumber.html">Lucky number</a>. %H A049781 Wikipedia, <a href="http://en.wikipedia.org/wiki/Lucky_number">Lucky number</a>. %Y A049781 Cf. A000959. %K A049781 nonn %O A049781 1,2 %A A049781 _Clark Kimberling_