login
Square array of distinct positive integers T(n, k), n > 0, k > 0, read by antidiagonals upwards, filled the greedy way such that for any n > 0 and k > 0, Sum_{ i = 1..n, j = 1..k } T(i, j) is divisible by n * k.
3

%I #11 Nov 18 2020 17:03:44

%S 1,3,5,2,7,6,10,12,8,4,9,16,19,14,24,11,15,31,27,18,20,13,17,21,43,30,

%T 22,38,23,33,41,47,40,48,26,46,36,63,35,39,88,70,44,62,45,32,66,55,71,

%U 52,60,28,42,29,51,25,86,90,67,98,56,54,34,73,91,57

%N Square array of distinct positive integers T(n, k), n > 0, k > 0, read by antidiagonals upwards, filled the greedy way such that for any n > 0 and k > 0, Sum_{ i = 1..n, j = 1..k } T(i, j) is divisible by n * k.

%C This sequence is a 2-dimensional variant of A019444.

%H Rémy Sigrist, <a href="/A338872/b338872.txt">Table of n, a(n) for n = 1..5050</a>

%H Rémy Sigrist, <a href="/A338872/a338872.gp.txt">PARI program for A338872</a>

%e Array T(n, k) begins:

%e n\k| 1 2 3 4 5 6 7 8 9 10

%e ---+-----------------------------------------------

%e 1| 1 5 6 4 24 20 38 46 45 51

%e 2| 3 7 8 14 18 22 26 62 29 91

%e 3| 2 12 19 27 30 48 44 42 73 53

%e 4| 10 16 31 43 40 70 28 34 61 37

%e 5| 9 15 21 47 88 60 54 106 77 133

%e 6| 11 17 41 39 52 56 50 118 129 157

%e 7| 13 33 35 71 98 116 173 117 181 213

%e 8| 23 63 55 67 82 136 155 187 141 161

%e 9| 36 66 90 84 99 111 179 143 146 256

%e 10| 32 86 74 124 109 121 203 235 78 188

%o (PARI) See Links section.

%Y See A338918 and A338919 for similar sequences.

%Y Cf. A019444.

%K nonn,look,tabl

%O 1,2

%A _Rémy Sigrist_, Nov 13 2020