A108616 3-column rectangular array of near-right obtuse triangles.

4, 8, 9, 6, 18, 19, 8, 32, 33, 18, 30, 35, 10, 50, 51, 22, 46, 51, 34, 38, 51, 12, 72, 73, 28, 76, 81, 44, 68, 81, 14, 98, 99, 32, 100, 105, 68, 80, 105, 16, 128, 129, 64, 112, 129, 38, 142, 147, 60, 132, 145, 18, 162, 163, 82, 122, 147, 72, 144, 161, 42, 174, 179

Offset

0,1

Links

Table of n, a(n) for n=0..62.

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 two triples:
4,8,9 (a + b + c = 21; 16 + 64 - 81 = -1)
6,18,19 (a + b + c = 43; 36 + 324 - 361 = -1)

Crossrefs

Cf. A108615.

Sequence in context: A194623 A366022 A316251 * A200634 A154177 A010480

Adjacent sequences: A108613 A108614 A108615 * A108617 A108618 A108619

Keyword

nonn,tabf

Author

Clark Kimberling, Jun 12 2005

Status

approved