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Irregular triangle read by rows: squarefree quadratic non-residues.
3

%I #11 Aug 03 2014 14:01:25

%S 2,2,3,2,3,2,5,3,5,6,2,3,5,6,7,2,3,5,6,2,3,7,2,6,7,10,2,3,5,6,7,10,11,

%T 2,5,6,7,11,3,5,6,10,13,2,3,5,7,11,13,14,2,3,5,6,7,10,11,13,14,15,3,5,

%U 6,7,10,11,14,2,3,5,6,11,14,15,17,2,3,10,13,14,15

%N Irregular triangle read by rows: squarefree quadratic non-residues.

%C The irregular triangle of numbers is:

%C ..n....Squarefree quadratic non-residues

%C ..1....

%C ..2....

%C ..3....2

%C ..4....2..3

%C ..5....2..3

%C ..6....2..5

%C ..7....3..5..6

%C ..8....2..3..5..6..7

%C ..9....2..3..5..6

%C .10....2..3..7

%C .11....2..6..7.10

%C .12....2..3..5..6..7.10.11

%C .13....2..5..6..7.11

%C .14....3..5..6.10.13

%C .15....2..3..5..7.11.13.14

%C .16....2..3..5..6..7.10.11.13.14.15

%C .17....3..5..6..7.10.11.14

%C .18....2..3..5..6.11.14.15.17

%C .19....2..3.10.13.14.15

%H C. H. Gribble, <a href="/A165916/b165916.txt">Flattened irregular triangle read by rows j = 3 to 200</a>

%t Flatten[Table[Select[Complement[Range[n - 1], Mod[Range[n/2]^2, n]], SquareFreeQ], {n, 3, 30}]] (* _T. D. Noe_, Nov 22 2011 *)

%Y Cf. A096013.

%K nonn,tabf

%O 3,1

%A _Christopher Hunt Gribble_, Sep 30 2009

%E Minor edit by _Christopher Hunt Gribble_, Oct 05 2009