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 A364884 #14 Aug 27 2023 14:37:39 %S A364884 1,2,4,3,6,8,5,10,12,9,7,14,16,15,18,11,20,24,21,30,32,13,22,28,27,36, %T A364884 40,25,17,26,44,33,42,48,35,50,19,34,52,39,54,56,45,60,72,23,38,64,51, %U A364884 66,80,55,70,84,63,29,46,68,57,78,88,65,90,96,81,49 %N A364884 Triangle T(n, k), n > 0, k = 1..n, read by rows; T(1, 1) = 1, and for n > 1, k = 1..n, T(n, k) is the least unseen multiple of the k-th term of the flattened sequence . %C A364884 In other words, T(n, k) is a multiple of a(k). %C A364884 As a flat sequence, this is a permutation of the positive integers (as each row starts with the least positive integer not yet in the sequence); see A364887 for the inverse permutation. %H A364884 Rémy Sigrist, <a href="/A364884/b364884.txt">Table of n, a(n) for n = 1..10011</a> (rows for n = 1..141 flattened) %H A364884 Rémy Sigrist, <a href="/A364884/a364884.gp.txt">PARI program</a> %H A364884 <a href="/index/Per#IntegerPermutation">Index entries for sequences that are permutations of the natural numbers</a> %e A364884 Triangle begins: %e A364884 1, %e A364884 2, 4 %e A364884 3, 6, 8 %e A364884 5, 10, 12, 9 %e A364884 7, 14, 16, 15, 18 %e A364884 11, 20, 24, 21, 30, 32 %e A364884 13, 22, 28, 27, 36, 40, 25 %e A364884 17, 26, 44, 33, 42, 48, 35, 50 %e A364884 19, 34, 52, 39, 54, 56, 45, 60, 72 %e A364884 23, 38, 64, 51, 66, 80, 55, 70, 84, 63 %e A364884 29, 46, 68, 57, 78, 88, 65, 90, 96, 81, 49 %e A364884 31, 58, 76, 69, 102, 104, 75, 100, 108, 99, 77, 98 %e A364884 .................................................. %e A364884 a(k) 1, 2, 4, 3, 6, 8, 5, 10, 12, 9, 7, 14 %o A364884 (PARI) See Links section. %Y A364884 See A361748 and A364885 for similar sequences. %Y A364884 Cf. A364887 (inverse). %K A364884 nonn,tabl %O A364884 1,2 %A A364884 _Rémy Sigrist_, Aug 12 2023