A113171 Short legs 'A' of exactly 7 primitive Pythagorean triangles.

660, 1092, 1140, 1155, 1260, 1320, 1365, 1380, 1428, 1540, 1560, 1740, 1785, 1820, 1860, 1980, 1995, 2184, 2220, 2340, 2380, 2415, 2436, 2460, 2508, 2580, 2604, 2660, 2805, 2820, 2856, 2860, 2940, 3003, 3036, 3060, 3108, 3120, 3135, 3180, 3192, 3220, 3300

Offset: 1

Author

Vladimir Joseph Stephan Orlovsky, Aug 25 2008

Keywords

• nonn

Examples

			Examples of triples: 660.779.1021, 660.989.1189, 660.2989.3061, 660.4331.4381, 660.12091.12109, 660.27221.27229, 660.108899.108901
1092.1325.1717, 1092.1595.1933, 1092.6035.6133, 1092.8245.8317, 1092.33115.33133, 1092.74525.74533, 1092.298115.298117
		

Links

• Ray Chandler, Table of n, a(n) for n = 1..10000

Crossrefs

Cf. A056866 Orders of non-solvable groups. A093006 Referring to the triangle in A093005, sequence contains the least term with maximal number of divisors. A138605 Short legs of more than 3 primitive Pythagorean triangles. A033993 Numbers that are divisible by exactly four different primes.

Programs

Mathematica

PythagoreanAs[a_]:=(q={};k=0;Do[y=(a^2+b^2)^0.5;c=IntegerPart[y];If[c==y,p=0;If[GCD[a,b,c]==1,AppendTo[q,a.b.c];k++ ]],{b,a+1,a^2}];PrependTo[q,k];q);lst={};Do[If[PythagoreanAs[n][[1]]==7,Print[n];AppendTo[lst,n]],{n,6*10^2,2*10^3}];lst

Formula

a^2+b^2=c^2

Extensions

More terms from Ray Chandler, Jan 22 2020