A087456 Palindromic hypotenuses in primitive Pythagorean triples.

5, 101, 181, 313, 353, 373, 505, 545, 565, 757, 797, 929, 949, 10001, 10201, 10301, 10501, 10601, 12421, 12721, 12821, 14341, 14741, 16061, 16361, 16561, 16661, 16861, 18181, 18281, 18481, 18581, 31013, 31313, 31513, 31613, 31813, 33133

Offset

1,1

Comments

For prime terms in this sequence, see A081220. - Lekraj Beedassy, Jun 30 2008

Links

Table of n, a(n) for n=1..38.

Mathematica

Take[Select[Sqrt[#[[1]]^2+#[[2]]^2]&/@(Union[Sort/@({Times@@#, (Last[#]^2- First[#]^2)/2}&/@(Select[Subsets[Range[1, 311, 2], {2}], GCD@@#== 1&]))]), PalindromeQ]//Union, 50] (* Requires Mathematica version 10 or later *) (* Harvey P. Dale, Sep 06 2018 *)

Crossrefs

Cf. A020882.

Sequence in context: A197200 A090436 A140616 * A081220 A210362 A041187

Adjacent sequences: A087453 A087454 A087455 * A087457 A087458 A087459

Keyword

nonn,base

Author

Lekraj Beedassy, Oct 23 2003

Extensions

More terms from Ray Chandler, Oct 25 2003

Status

approved