%I #18 Jul 22 2024 11:23:12
%S 0,1,2,4,3,5,6,7,8,9,11,13,12,17,18,24,10,14,15,16,19,20,22,26,21,23,
%T 25,27,28,29,30,31,32,33,34,35,37,39,41,43,38,42,47,48,51,52,58,62,40,
%U 49,50,60,59,61,70,71,72,73,83,85,84,97,98,112,36,44,45,46,53,54
%N Irregular triangle T(n, k), n >= 0, k = 1..A120880(n), read by rows; the n-th lists the integers m such that A374560(m) = n.
%C A374560 corresponds to a square array, but we consider it here as a flat sequence (when its values are read according along its antidiagonals).
%C As a flat sequence, this is a permutation of the nonnegative integers with inverse A374792.
%H Rémy Sigrist, <a href="/A374791/b374791.txt">Table of n, a(n) for n = 0..8255</a>
%H Rémy Sigrist, <a href="/A374791/a374791.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 n n-th row
%e -- ------------------------------
%e 0 0
%e 1 1, 2
%e 2 4
%e 3 3, 5
%e 4 6, 7, 8, 9
%e 5 11, 13
%e 6 12
%e 7 17, 18
%e 8 24
%e 9 10, 14
%e 10 15, 16, 19, 20
%e 11 22, 26
%e 12 21, 23, 25, 27
%e 13 28, 29, 30, 31, 32, 33, 34, 35
%e 14 37, 39, 41, 43
%e 15 38, 42
%o (PARI) \\ See Links section.
%Y Cf. A120880, A374560, A374792 (inverse).
%K nonn,tabl,base
%O 0,3
%A _Rémy Sigrist_, Jul 20 2024