|
|
A352360
|
|
Three-column array giving list of primitive triples for integer-sided triangles with A < B < C < 2*Pi/3 and such that FA, FB, FC are also integers where F is the Fermat point of the triangle.
|
|
0
|
|
|
399, 455, 511, 511, 616, 665, 1591, 5439, 5624, 35941, 47544, 58015, 8827, 16835, 18928, 36741, 73151, 92680, 16219, 94335, 97976, 1235, 4056, 4459, 12728, 13545, 15523, 14744, 33271, 37539, 13889, 16856, 17501, 1911, 4901, 5681, 196935, 320624, 324079, 9435, 12691, 17501, 22477, 37128, 44135
(list;
graph;
refs;
listen;
history;
text;
internal format)
|
|
|
OFFSET
|
1,1
|
|
COMMENTS
|
Inspired by Project Euler, Problem 143 (see link) where such a triangle is called a Torricelli triangle.
Differs from A336328 where FA + FB + FC is an integer, but FA, FB and FC are fractions. Jinyuan Wang has found that the 37th and 58th triples are the first triples for which the common denominator of these fractions is 1 (A351477).
Each triple (a, b, c) is in increasing order, and the triples are displayed in the same increasing order of the corresponding triples in A336328 (see formulas).
+-------+-------+-------+---------+--------+-------+-------+--------+--------+
| a | b | c |gcd(a,b,c)| FA | FB | FC | d | a+b+c |
+-------+-------+-------+----------+-------+-------+-------+--------+--------+
| 399 | 455 | 511 | 7 | 325 | 264 | 195 | 784 | 1365 |
| 511 | 616 | 665 | 7 | 440 | 325 | 264 | 1029 | 1792 |
| 1591 | 5439 | 5624 | 37 | 5016 | 1064 | 765 | 6845 | 12654 |
| 35941 | 47544 | 58015 | 283 | 39360 | 27265 | 13464 | 80089 | 141500 |
| 8827 | 16835 | 18928 | 91 | 14800 | 6528 | 3515 | 24843 | 44590 |
| 36741 | 73151 | 92680 | 331 | 70720 | 34200 | 4641 | 109561 | 202572 |
| 16219 | 94335 | 97976 | 331 | 91200 | 12376 | 5985 | 109561 | 208530 |
| 1235 | 4056 | 4459 | 13 | 3864 | 1015 | 360 | 5239 | 9750 |
| 12728 | 13545 | 15523 | 43 | 9405 | 8512 | 6120 | 24037 | 41796 |
| 14744 | 33271 | 37539 | 97 | 30429 | 11520 | 5096 | 47045 | 87554 |
..............................................................................
The sequences with terms of this table are listed in Crossrefs section; here, d = FA + FB + FC. The perimeter corresponding to n-th triple a+b+c = A336333(n) * A351477(n).
|
|
LINKS
|
|
|
FORMULA
|
|
|
EXAMPLE
|
The array begins:
399, 455, 511;
511, 616, 665;
1591, 5439, 5624;
35941, 47544, 58015;
8827, 16835, 18928;
36741, 73151, 92680;
.....................
For 1st triple (399, 455, 511) with gcd(399, 455, 511) = 7, we get FA = 325, FB = 264 and FC = 195. This smallest triangle such that a, b, c, FA, FB, FC are all integers is the example proposed in Project Euler's link.
|
|
CROSSREFS
|
|
|
KEYWORD
|
nonn,tabf
|
|
AUTHOR
|
|
|
STATUS
|
approved
|
|
|
|