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 A361507 #18 Jul 09 2025 05:00:31 %S A361507 1,3,7,16,37,84,190,428,964,2170,4883,10987,24721,55623,125152,281593, %T A361507 633585,1425567,3207526,7216934,16238102,36535730,82205393,184962135, %U A361507 416164804,936370810,2106834323,4740377227,10665848761,23998159713,53995859355,121490683549,273354037986,615046585469,1383854817306,3113673338939 %N A361507 a(0) = 1; thereafter a(n) = floor((9/4)*a(n-1)) + 1. %D A361507 N. Tokuda, An efficient Shell's method of sorting by generalized scheme, Department of Computer Science, Utunomiya University, 1989; 10 pages plus 9 unnumbered pages of tables and charts. %H A361507 Paolo Xausa, <a href="/A361507/b361507.txt">Table of n, a(n) for n = 0..1000</a> %t A361507 NestList[Floor[9/4#]+1&,1,50] (* _Paolo Xausa_, Dec 02 2023 *) %Y A361507 Other sequences used for Shell sort: A003462, A033622, A036562, A036564, A036569, A055875, A055876, A108870, A361506. %K A361507 nonn %O A361507 0,2 %A A361507 _N. J. A. Sloane_, Mar 20 2023, following a suggestion from _Don Knuth_