A108615 - OEIS

A108615

3-column rectangular array of near-right acute triangles.

4, 7, 8, 8, 9, 12, 7, 11, 13, 6, 17, 18, 11, 13, 17, 10, 15, 18, 9, 19, 21, 14, 17, 22, 13, 19, 23, 17, 21, 27, 16, 23, 28, 8, 31, 32, 11, 29, 31, 15, 26, 30, 20, 25, 32, 14, 31, 34, 19, 27, 33, 17, 34, 38, 23, 29, 37, 22, 31, 38, 13, 41, 43, 16, 41, 44, 26, 33, 42, 25, 35, 43, 10

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OFFSET

0,1

LINKS

Table of n, a(n) for n=0..72.

FORMULA

Row n is the n-th triple (a, b, c), in order of increasing perimeter a+b+c and increasing a, such that a < b < c and a^2 + b^2 - c^2 = 1.

EXAMPLE

First five triples:

4,7,8 (a + b + c = 19; 16 + 49 - 64 = 1)

8,9,12 (a + b + c = 29; 64 + 81 - 144 = 1)

7,11,13 (a + b + c = 31)