The On-Line Encyclopedia of Integer Sequences (OEIS)

Revision History for A097102 (Bold, blue-underlined text is an addition; faded, red-underlined text is a ~~deletion~~.)
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A097102

Numbers n that are the hypotenuse of exactly 13 distinct integer-sided right triangles, i.e., n^2 can be written as a sum of two squares in 13 ways.
(history; published version)

#21 by Ray Chandler at Mon Dec 30 10:14:26 EST 2019

STATUS

editing

approved

#20 by Ray Chandler at Mon Dec 30 10:14:22 EST 2019

COMMENTS

If m is a term, then 2*m and p*m are terms where p is any prime of the form 4k+3. - Ray Chandler, Dec 30 2019

STATUS

approved

editing

#19 by Ray Chandler at Sun Aug 13 12:52:14 EDT 2017

STATUS

editing

approved

#18 by Ray Chandler at Sun Aug 13 12:52:10 EDT 2017

CROSSREFS

Cf. A004144 (0), A084645, (1), A084646, (2), A084647, (3), A084648, (4), A084649 (5), A097219 (6), A097101 (7), A290499 (8), A290500 (9), A097225 (10), A290501 (11), A097226 (12), A290502 (14), A290503 (15), A097238 (16), A097239 (17), A290504 (18), A290505 (19), A097103 (22), A097244 (31), A097245 (37), A097282 (40), A097626 (67).

STATUS

approved

editing

#17 by Jon E. Schoenfield at Wed Jul 26 20:25:58 EDT 2017

STATUS

editing

approved

#16 by Jon E. Schoenfield at Wed Jul 26 20:25:55 EDT 2017

NAME

Numbers n that are the hypotenuse of exactly 13 distinct integer -sided right triangles, i.e. , n^2 can be written as a sum of two squares in 13 ways.

STATUS

approved

editing

#15 by Bruno Berselli at Tue Mar 01 03:14:06 EST 2016

STATUS

reviewed

approved

#14 by Joerg Arndt at Tue Mar 01 03:06:06 EST 2016

STATUS

proposed

reviewed

#13 by Vincenzo Librandi at Tue Mar 01 01:20:34 EST 2016

STATUS

editing

proposed

#12 by Vincenzo Librandi at Tue Mar 01 01:20:15 EST 2016

MATHEMATICA

r[a_]:={b, c}/.{ToRules[Reduce[0<b<c&&a^2 == b^2 + c^2, {b, c}, Integers]]}; Select[Range[5000], Length[r[#]] == 13 &] (* Vincenzo Librandi, Mar 01 2016 *)

STATUS

proposed

editing