A165913 Irregular triangle read by rows: Squarefree nonzero quadratic residues.

1, 1, 1, 1, 1, 3, 1, 2, 1, 1, 7, 1, 5, 6, 1, 3, 5, 1, 1, 3, 10, 1, 2, 7, 11, 1, 6, 10, 1, 1, 2, 13, 15, 1, 7, 10, 13, 1, 5, 6, 7, 11, 17, 1, 5, 1, 7, 15, 1, 3, 5, 11, 14, 15, 1, 2, 3, 6, 13, 1, 1, 6, 11, 14, 19, 21, 1, 3, 10, 13, 14, 17, 22, 23, 1, 7, 10, 13, 19, 22, 1, 21, 1, 5, 6, 7, 13, 22, 23

Offset: 1

Author

Christopher Hunt Gribble, Sep 30 2009

Keywords

• nonn
• tabf

Comments

The irregular triangle of numbers is:

..n....Squarefree nonzero quadratic residues

..1....

..2....1

..3....1

..4....1

..5....1

..6....1..3

..7....1..2

..8....1

..9....1..7

.10....1..5..6

.11....1..3..5

.12....1

.13....1..3.10

.14....1..2..7.11

.15....1..6.10

.16....1

.17....1..2.13.15

.18....1..7.10.13

.19....1..5..6..7.11.17

.20....1..5

.21....1..7.15

.22....1..3..5.11.14.15

.23....1..2..3..6.13

.24....1

.25....1..6.11.14.19.21

.26....1..3.10.13.14.17.22.23

.27....1..7.10.13.19.22

.28....1.21

.29....1..5..6..7.13.22.23

Links

• C. H. Gribble, Flattened irregular triangle read by rows as table of j, a(j) for j = 1: 78998 (rows 2:1000).

Crossrefs

Cf. A046071.

Extensions

Minor edit by Christopher Hunt Gribble, Oct 05 2009