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

1,6

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.

Sequence in context: A139436 A212305 A205555 * A256253 A288818 A319658

Adjacent sequences: A165910 A165911 A165912 * A165914 A165915 A165916

Keyword

nonn,tabf

Author

Christopher Hunt Gribble, Sep 30 2009

Extensions

Minor edit by Christopher Hunt Gribble, Oct 05 2009

Status

approved