A165919 - OEIS

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

(list; graph; refs; listen; history; text; internal format)

OFFSET

5,1

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.

Sequence in context: A049109 A035651 A007208 * A035637 A001736 A247969

Adjacent sequences: A165916 A165917 A165918 * A165920 A165921 A165922

KEYWORD

nonn,tabf

AUTHOR

Christopher Hunt Gribble, Sep 30 2009

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

STATUS

approved