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 A271589 #20 Feb 16 2025 08:33:33 %S A271589 1,3,2,8,5,4,17,9,6,7,44,20,11,12,10,125,47,24,15,14,13,368,128,51,26, %T A271589 18,21,16,1097,371,132,53,27,35,23,19,3284,1100,375,134,56,29,36,30, %U A271589 22,9845,3287,1104,377,137,60,33,38,32,25,29528,9848,3291,1106 %N A271589 Array read by antidiagonals: column k lists the 2-Stöhr sequence composed of terms rejected from column k-1. %C A271589 The first column of this array is the sequence that rejects the sum of any previous pair of terms (the 2-Stöhr sequence A033627). The second column takes the remaining numbers and rejects the sums of pairs of its previous terms, etc. %C A271589 The first column consists of all numbers equivalent to 1 mod 3, and also 2. The second column consists of all numbers equivalent to 3 mod 9 and 5 mod 9, and also 6. The k-th column includes 3^k, 2*3^k, and 4*3^k, and in general every term in the (k-1)-th column multiplied by 3. %H A271589 Max Barrentine, <a href="/A271589/b271589.txt">Table of n, a(n) for n = 1..2080</a> %H A271589 Eric Weisstein's World of Mathematics, <a href="https://mathworld.wolfram.com/StoehrSequence.html">Stöhr Sequence</a> %e A271589 From the top-left corner, this array starts: %e A271589 1 3 8 17 44 125 %e A271589 2 5 9 20 47 128 %e A271589 4 6 11 24 51 132 %e A271589 7 12 15 26 53 134 %e A271589 10 14 18 27 56 137 %e A271589 13 21 35 29 60 141 %Y A271589 Cf. A033627. %K A271589 nonn,tabl %O A271589 1,2 %A A271589 _Max Barrentine_, Apr 10 2016