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 A095912 #17 Apr 12 2023 11:18:15 %S A095912 1,2,4,6,12,28,104,152,528,2208,9120,23616,130944,278784,1635840, %T A095912 14181120,32186880,116674560,1262039040,2443714560,58920099840, %U A095912 161981890560,1416311930880,7700720025600,120779469619200 %N A095912 Variant of the pay-phone sequence A095236. Here a slot at the end of the row is always preferred over a slot sandwiched immediately between two used slots. %H A095912 Max Alekseyev, <a href="/A095912/b095912.txt">Table of n, a(n) for n = 1..100</a> %H A095912 Max A. Alekseyev, <a href="https://arxiv.org/abs/2304.04324">Enumeration of Payphone Permutations</a>, arXiv:2304.04324 [math.CO], 2023. %H A095912 Simon Wundling, <a href="https://arxiv.org/abs/2303.18175">About a combinatorial problem with n seats and n people</a>, arXiv:2303.18175 [math.CO], 2023. (German) %e A095912 Example: there are 5 payphones. First arrival may choose any; he selects phone #2. Next arrival must take the furthest away, #5. Next arrival must take either of #3 or #4 (since both have a neighbor on one side and a vacant slot on the other); he chooses #3. Next arrival must take #1 (because end slots are preferred over "sandwiched" slots), leaving #4 for the last arrival. The permutation (25314) is one of a(5)=10 that satisfy the requirements. %Y A095912 Cf. A095236, A095239, A095240, A095923. %K A095912 nonn %O A095912 1,2 %A A095912 _Jon Wild_, Jul 13 2004 %E A095912 Corrected and extended by _Don Reble_, Jul 15 2004