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

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)
6,17,18 (a + b + c = 41)
11,13,17 (a + b + c = 41)

Crossrefs

Cf. A108616.

Sequence in context: A332504 A121488 A115291 * A310937 A090383 A179620

Adjacent sequences: A108612 A108613 A108614 * A108616 A108617 A108618

Keyword

nonn,tabf

Author

Clark Kimberling, Jun 12 2005

Status

approved