OFFSET
4,2
LINKS
Peter Kagey, Table of n, a(n) for n = 4..150
Peter Kagey, Integer Triangles with perimeter less than n, Programming Puzzles & Code Golf Stack Exchange.
FORMULA
a(n) = Sum_{k=3..n-1} A298079(k).
EXAMPLE
All a(7) = 11 triangles with integer coordinates and perimeter less than 7 are congruent to triangles with coordinates:
(0, 0), (0, 1), (1, 0) - with perimeter ~3.41; or
(0, 0), (1, 2), (0, 1) - with perimeter ~4.65; or
(0, 0), (0, 2), (1, 1) - with perimeter ~4.82; or
(0, 0), (0, 2), (1, 0) - with perimeter ~5.23; or
(0, 0), (1, 2), (2, 1) - with perimeter ~5.88; or
(0, 0), (2, 2), (0, 1) - with perimeter ~6.06; or
(0, 0), (1, 3), (0, 1) - with perimeter ~6.39; or
(0, 0), (0, 2), (2, 1) - with perimeter ~6.47; or
(0, 0), (1, 3), (0, 2) - with perimeter ~6.57; or
(0, 0), (0, 3), (1, 1) - with perimeter ~6.65; or
(0, 0), (0, 2), (2, 0) - with perimeter ~6.82.
CROSSREFS
KEYWORD
nonn
AUTHOR
Peter Kagey, Jan 12 2018
STATUS
approved