A165919 Irregular triangle read by rows: square-full nonzero quadratic residues mod n.

4, 4, 4, 4, 4, 4, 9, 4, 9, 4, 9, 4, 9, 12, 4, 8, 9, 4, 9, 4, 9, 4, 8, 9, 16, 4, 9, 16, 4, 9, 16, 4, 9, 16, 4, 9, 16, 18, 4, 9, 12, 16, 20, 4, 8, 9, 12, 16, 18, 4, 9, 12, 16, 4, 9, 16, 24, 4, 9, 12, 16, 25, 4, 9, 16, 25, 4, 8, 9, 16, 25, 4, 9, 16, 20, 24, 25, 28, 4, 9, 16, 24, 25

Offset: 5

Author

Christopher Hunt Gribble, Sep 30 2009

Keywords

• nonn
• tabf

Comments

The irregular triangle of numbers is:

..n....Square-full nonzero quadratic residues

..1....

..2....

..3....

..4....

..5.....4

..6.....4

..7.....4

..8.....4

..9.....4

.10.....4..9

.11.....4..9

.12.....4..9

.13.....4..9.12

.14.....4..8..9

.15.....4..9

.16.....4..9

.17.....4..8..9.16

.18.....4..9.16

.19.....4..9.16

.20.....4..9.16

.21.....4..9.16.18

.22.....4..9.12.16.20

.23.....4..8..9.12.16.18

.24.....4..9.12.16

.25.....4..9.16.24

.26.....4..9.12.16.25

.27.....4..9.16.25

.28.....4..8..9.16.25

.29.....4..9.16.20.24.25

.30.....4..9.16.24.25

Links

• C. H. Gribble, Flattened irregular triangle read by rows as table of j, a(j) for j = 5..69744 (rows 5:1000). [Entries in b-file edited by _N. J. A. Sloane_, Oct 04 2010]

Crossrefs

Cf. A046071.

Extensions

Minor edit and cross-reference added by Christopher Hunt Gribble, Oct 05 2009

Offset set to 5, keyword:tabf added - R. J. Mathar, Oct 09 2009