%I
%S 1,2,3,5,7,4,6,8,9,11,13,17,19,10,12,14,15,16,21,23,25,27,29,31,37,20,
%T 18,22,26,28,24,30,33,41,35,39,43,45,47,49,53,32,34,38,40,36,44,46,48,
%U 50,51,55,59,61,57,65,67,63,71,73,77,52,42,54,56,58,62,64,68,74,60,69
%N Triangle read by rows where T(0,0) is 1, T(m,n) = smallest asyetunused (reading rows from left to right) positive integer which is coprime to both T(m1,n) and T(m1,n1) (or is coprime to T(m1,0) if n=0, or to T(m1,m1) if n=m).
%C In other words, a minimal sequence representing a square array (read by antidiagonals) in which every number is coprime to all four closest neighbors.  _Ivan Neretin_, Jun 05 2015
%H Ivan Neretin, <a href="/A097883/b097883.txt">Table of n, a(n) for n = 0..5049</a>
%e T(3,2)=9 is smallest asyetunused positive integer coprime to both T(2,1)=7 and T(2,2)=4.
%e T(4,0)=13 is smallest asyetunused positive integer coprime to T(3,0)=6.
%e Triangle begins:
%e 1
%e 2, 3
%e 5, 7, 4
%e 6, 8, 9, 11
%e 13,17,19,10,12
%e 14,15,16,21,23,25
%t a[0, 0] = 1; a[m_, n_] := a[m, n] = Block[{k = 2, p = Sort[ Flatten[ Join[ Table[ a[i, j], {i, 0, m  1}, {j, 0, i}], Table[ a[i, j], {i, m, m}, {j, 0, n  1}]] ]]}, While[ Position[p, k] != {}  If[n == 0, GCD[k, a[m  1, 0]] != 1, If[n == m, GCD[k, a[m  1, m  1]] != 1, GCD[k, a[m  1, n]] != 1  GCD[k, a[m  1, n  1]] != 1]], k++ ]; k]; Flatten[ Table[ a[m, n], {m, 0, 10}, {n, 0, m}]] (* _Robert G. Wilson v_, Sep 04 2004 *)
%K nonn,tabl
%O 0,2
%A _Leroy Quet_, Sep 02 2004
%E More terms from _Robert G. Wilson v_, Sep 04 2004
