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A279433 Triangle read by rows: T(n,k), n>=k>=1, is the number of right triangles with integral coordinates that have a bounding box of size n X k. 9
0, 0, 4, 0, 6, 4, 0, 4, 12, 4, 0, 4, 6, 12, 12, 0, 4, 8, 12, 12, 4, 0, 4, 4, 6, 12, 20, 4, 0, 4, 4, 12, 12, 12, 20, 4, 0, 4, 4, 4, 14, 12, 20, 12, 12, 0, 4, 4, 4, 12, 12, 16, 12, 12, 20, 0, 4, 4, 8, 8, 6, 12, 20, 20, 20, 4, 0, 4, 4, 4, 4, 12, 28, 12, 12, 12 (list; table; graph; refs; listen; history; text; internal format)
OFFSET
1,3
LINKS
Lars Blomberg, Table of n, a(n) for n = 1..9870 (the first 140 rows)
EXAMPLE
Triangle begins:
0
0,4
0,6,4
0,4,12,4
0,4,6,12,12
0,4,8,12,12,4
0,4,4,6,12,20,4
0,4,4,12,12,12,20,4
0,4,4,4,14,12,20,12,12
0,4,4,4,12,12,16,12,12,20
0,4,4,8,8,6,12,20,20,20,4
0,4,4,4,4,12,28,12,12,12,20,4
0,4,4,4,4,12,6,20,20,16,20,20,12
0,4,4,4,12,4,24,12,12,12,20,12,20,4
0,4,4,4,4,4,12,6,28,20,12,20,20,20,4
0,4,4,4,4,4,8,12,20,20,12,20,12,20,28,4
0,4,4,4,4,12,4,12,18,12,20,12,28,12,20,20,28
-----
The right angle is 'o'.
For n=2, k=2:
ox xo x. .x
x. .x ox xo
So T(2,2)=4
-----
For n=3, k=2:
o.x x.x x.o x.. .o. ..x
x.. .o. ..x o.x x.x x.o
So T(3,2)=6
CROSSREFS
Cf. A077435.
See A279415 for right isosceles triangles.
See A280639 for obtuse isosceles triangles.
See A279418 for acute isosceles triangles.
See A279413 for all isosceles triangles.
See A280652 for all obtuse triangles.
See A280653 for all acute triangles.
See A279432 for all triangles.
Sequence in context: A226775 A338682 A305731 * A096272 A340949 A021715
KEYWORD
nonn,tabl
AUTHOR
Lars Blomberg, Feb 27 2017
STATUS
approved

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Last modified July 12 17:07 EDT 2024. Contains 374251 sequences. (Running on oeis4.)