A165925 Irregular triangle read by rows: square-full quadratic non-residues.

8, 8, 8, 8, 8, 12, 8, 12, 8, 12, 12, 8, 12, 8, 12, 18, 8, 12, 18, 8, 12, 20, 8, 18, 20, 8, 18, 20, 8, 12, 18, 20, 8, 18, 20, 24, 8, 12, 18, 20, 24, 12, 18, 20, 24, 27, 8, 12, 18, 27, 8, 12, 18, 20, 27, 28, 12, 24, 27, 8, 12, 18, 20, 24, 27, 28, 8, 18, 20, 24, 28, 32, 12, 20, 24, 27, 28

Offset

9,1

Comments

The irregular triangle of numbers is:

..n....Square-full quadratic non-residues

..1....

..2....

..3....

..4....

..5....

..6....

..7....

..8....

..9.....8

.10.....8

.11.....8

.12.....8

.13.....8

.14....12

.15.....8.12

.16.....8.12

.17....12

.18.....8.12

.19.....8.12.18

.20.....8.12.18

.21.....8.12.20

.22.....8.18

.23....20

.24.....8.18.20

.25.....8.12.18.20

.26.....8.18.20.24

.27.....8.12.18.20.24

.28....12.18.20.24.27

.29.....8.12.18.27

.30.....8.12.18.20.27.28

.31....12.24.27

.32.....8.12.18.20.24.27.28

.33.....8.18.20.24.28.32

.34....12.20.24.27.28

Links

C. H. Gribble, Flattened irregular triangle read by rows j = 9 to 200

Mathematica

Flatten[Table[Select[Complement[Range[n - 1], Mod[Range[n/2]^2, n]], ! SquareFreeQ[#] &], {n, 9, 34}]] (* T. D. Noe, Nov 22 2011 *)

Crossrefs

Cf. A096013.

Sequence in context: A245401 A048763 A088841 * A165926 A216865 A216412

Adjacent sequences: A165922 A165923 A165924 * A165926 A165927 A165928

Keyword

nonn,tabf

Author

Christopher Hunt Gribble, Sep 30 2009

Status

approved