A365230 - OEIS

A365230

Triangle T(n, k), n > 0, k = 1..n, read by rows and filled the greedy way with distinct positive integers such that T(n, k) is a multiple of T(k, 1).

%I #13 Aug 31 2023 15:52:25

%S 1,2,4,3,6,9,5,8,12,10,7,14,15,20,21,11,16,18,25,28,22,13,24,27,30,35,

%T 33,26,17,32,36,40,42,44,39,34,19,38,45,50,49,55,52,51,57,23,46,48,60,

%U 56,66,65,68,76,69,29,54,63,70,77,88,78,85,95,92,58

%N Triangle T(n, k), n > 0, k = 1..n, read by rows and filled the greedy way with distinct positive integers such that T(n, k) is a multiple of T(k, 1).

%C As a flat sequence, this is a permutation of the positive integers (as each row starts with the least value not yet in the sequence); see A365231 for the inverse.

%H Rémy Sigrist, <a href="/A365230/b365230.txt">Table of n, a(n) for n = 1..10011</a> (rows for n = 1..141 flattened)

%H Rémy Sigrist, <a href="/A365230/a365230.gp.txt">PARI program</a>

%H <a href="/index/Per#IntegerPermutation">Index entries for sequences that are permutations of the natural numbers</a>

%e Triangle T(n, k) begins:

%e 1;

%e 2, 4;

%e 3, 6, 9;

%e 5, 8, 12, 10;

%e 7, 14, 15, 20, 21;

%e 11, 16, 18, 25, 28, 22;

%e 13, 24, 27, 30, 35, 33, 26;

%e 17, 32, 36, 40, 42, 44, 39, 34;

%e 19, 38, 45, 50, 49, 55, 52, 51, 57;

%e ...................................

%e T(k, 1) 1 2 3 5 7 11 13 17 19

%o (PARI) See Links section.

%Y See A364884 and A365232 for similar sequences.

%Y Cf. A365231 (inverse).

%K nonn,tabl

%O 1,2

%A _Rémy Sigrist_, Aug 27 2023