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.

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

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

Adjacent sequences: A279430 A279431 A279432 * A279434 A279435 A279436

Keyword

nonn,tabl

Author

Lars Blomberg, Feb 27 2017

Status

approved