%I #12 Jun 07 2019 11:09:24

%S 1,2,3,3,4,5,3,6,7,8,4,9,10,11,12,5,13,14,15,16,17,3,18,19,20,21,22,

%T 23,6,24,25,26,27,28,29,30,7,31,32,33,34,35,36,37,38,8,39,40,41,42,43,

%U 44,45,46,47,4,48,49,50,51,52,53,54,55,56,57,9,58,59,60,61,62,63,64,65,66,67,68,10,69,70,71,72,73,74,75,76,77,78,79,80,11

%N Reading the first row of this array or its successive antidiagonals is the same as reading this sequence.

%C The array is always extended by its antidiagonals with the smallest term not yet present that doesn't lead to a contradiction. The sequence is thus the lexicographically earliest of its kind.

%F a(n*(n-1)/2 + 1) = a(n). - _Rémy Sigrist_, May 21 2019

%e Array:

%e 1 2 3 3 4 5 3 6 7 8 4 ...

%e 3 4 6 9 13 18 24 31 39 48 58 ...

%e 5 7 10 14 19 25 32 40 49 59 70 ...

%e 8 11 15 20 26 33 41 50 60 71 83 ...

%e 12 16 21 27 34 42 51 61 72 84 97 ...

%e 17 22 28 35 43 52 62 73 85 98 112 ...

%e 23 29 36 44 53 63 74 86 99 113 128 ...

%e 30 37 45 54 64 75 87 100 114 129 145 ...

%e 38 46 55 65 76 88 101 115 130 146 163 ...

%e 47 56 66 77 89 102 116 131 147 164 182 ...

%e 57 67 78 90 103 117 132 148 165 183 202 ...

%e ...

%Y Cf. A325783 and A325785 where the same idea is developed.

%Y Cf. A000124.

%K nonn,tabl

%O 1,2

%A _Eric Angelini_, May 21 2019