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A165974
Irregular triangle read by rows: floor(j^2 / p) for p prime and j = 1 to p-1.
12
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
1,7
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
CROSSREFS
Cf. A165993 (row sums).
Sequence in context: A151859 A163541 A280815 * A090622 A035696 A170840
KEYWORD
nonn,tabf
AUTHOR
EXTENSIONS
Keyword:tabf added by R. J. Mathar, Oct 09 2009
STATUS
approved