A165974 Irregular triangle read by rows: floor(j^2 / p) for p prime and j = 1 to p-1.

0, 0, 1, 0, 0, 1, 3, 0, 0, 1, 2, 3, 5, 0, 0, 0, 1, 2, 3, 4, 5, 7, 9, 0, 0, 0, 1, 1, 2, 3, 4, 6, 7, 9, 11, 0, 0, 0, 0, 1, 2, 2, 3, 4, 5, 7, 8, 9, 11, 13, 15, 0, 0, 0, 0, 1, 1, 2, 3, 4, 5, 6, 7, 8, 10, 11, 13, 15, 17, 0, 0, 0, 0, 1, 1, 2, 2, 3, 4, 5, 6, 7, 8, 9, 11, 12, 14, 15, 17, 19, 21

Offset: 1

Author

Christopher Hunt Gribble, Oct 02 2009

Keywords

• nonn
• tabf

Comments

The irregular triangle of numbers is:

....j..1..2..3..4..5..6..7..8..9.10.11.12.13.14.15.16.17.18.19.20.21.22

..p

..2....0

..3....0..1

..5....0..0..1..3

..7....0..0..1..2..3..5

.11....0..0..0..1..2..3..4..5..7..9

.13....0..0..0..1..1..2..3..4..6..7..9.11

.17....0..0..0..0..1..2..2..3..4..5..7..8..9.11.13.15

.19....0..0..0..0..1..1..2..3..4..5..6..7..8.10.11.13.15.17

.23....0..0..0..0..1..1..2..2..3..4..5..6..7..8..9.11.12.14.15.17.19.21

Links

• C. H. Gribble, Flattened irregular triangle read by rows of primes < 300

Crossrefs

Cf. A165993 (row sums).

Extensions

Keyword:tabf added by R. J. Mathar, Oct 09 2009