A343895 Perimeters of integer-sided primitive triangles (a, b, c) where side a is the harmonic mean of the two other sides b and c, i.e., 2/a = 1/b + 1/c with b < a.

13, 37, 47, 71, 73, 107, 121, 143, 177, 181, 183, 191, 239, 241, 249, 253, 291, 299, 337, 347, 359, 409, 421, 429, 431, 433, 491, 517, 503, 529, 537, 541, 563, 579, 587, 649, 659, 661, 671, 743, 753, 759, 767, 769, 781, 789, 793, 831, 851, 897, 863, 913, 923, 933, 937, 947, 971, 1033

Offset

1,1

Comments

This sequence is the list of ordered terms of A343894, which is not monotonic.

It first differs from A343894 at index 9 where a(9) = 177 while A343894(9) = 183.

Like A343894, all terms are odd.

For the corresponding primitive triples and miscellaneous properties and references, see A343891.

Links

Table of n, a(n) for n=1..58.

Example

a(2) = 12 + 10 + 15 = 37, because the second largest perimeter corresponds to triple (12, 10, 15) with relations 2/12 = 1/10 + 1/15 and 15 - 10 < 12 < 15 + 10.

Crossrefs

Cf. A343894.

Cf. A343891, A343892, A343893.

Cf. A020883 (sides a), A020886 (sides c), A020890 (sides b).

Sequence in context: A285887 A063913 A119705 * A343894 A155560 A353198

Adjacent sequences: A343892 A343893 A343894 * A343896 A343897 A343898

Keyword

nonn

Author

Bernard Schott, May 18 2021

Status

approved