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 A364882 #30 Aug 27 2023 04:37:13 %S A364882 1,1,2,3,3,3,3,4,6,6,7,7,7,7,7,7,9,9,9,11,11,11,14,15,15,15,15,17,18, %T A364882 18,18,19,19,25,25,25,25,26,26,26,26,26,27,27,27,28,28,28,28,29,29,29, %U A364882 29,29,29,29,29,29,29,29,29,29,30,30,30,30,30,30,40,40 %N A364882 a(1)=1 and thereafter a(n) is the number of locations 1..n-1 which are visited last in a single path beginning at some location s, in which one proceeds from location i to i +- a(i) (within 1..n-1) until no further unvisited location is available. %C A364882 A location can be visited no more than once in a single path. %H A364882 Kevin Ryde, <a href="/A364882/b364882.txt">Table of n, a(n) for n = 1..246</a> %H A364882 Kevin Ryde, <a href="/A364882/a364882.c.txt">C Code</a> %e A364882 a(9)=6 because there are 6 locations which can be visited last (as a dead end) among i=1..8. The 6 locations are i=1,2,3,5,7,8. The following shows a path in which the last location is i=5, beginning at location s=8: %e A364882 1 2 3 4 5 6 7 8 location number i %e A364882 1,1,2,3,3,3,3,4 a(i) %e A364882 1<----3<------4 %e A364882 1>1>2-->3 %e A364882 From i=5, the only jumps are back to i=1 or forward to i=8, both of which were already visited, so i=5 is one possible dead end term. Here is a path illustrating how i=7 can be a dead end term. We begin at s=4. %e A364882 1 2 3 4 5 6 7 8 location number i %e A364882 1,1,2,3,3,3,3,4 a(i) %e A364882 3---->3 %e A364882 From i=7, we can only jump back to i=4, which was already visited, so i=7 is a dead end term. There are 4 other locations which can be last (or dead ends), for a total of 6 such locations, so a(9)=6. %Y A364882 Cf. A364392, A360744, A360593. %K A364882 nonn %O A364882 1,3 %A A364882 _Neal Gersh Tolunsky_, Aug 11 2023 %E A364882 More terms from _Kevin Ryde_, Aug 26 2023