|
| |
|
|
A020886
|
|
Ordered semiperimeters of primitive Pythagorean triangles.
|
|
26
| |
|
|
6, 15, 20, 28, 35, 42, 45, 63, 66, 72, 77, 88, 91, 99, 104, 110, 117, 120, 130, 143, 153, 156, 165, 170, 187, 190, 195, 204, 209, 210, 221, 228, 231, 238, 247, 255, 266, 272, 273, 276, 285, 299, 304, 322, 323, 325, 336, 342, 345, 350, 357, 368, 378, 391, 399
(list; graph; refs; listen; history; internal format)
|
|
|
|
OFFSET
| 1,1
|
|
|
COMMENTS
| n is in this sequence iff A078926(n)>0. This is a subset of A005279.
|
|
|
FORMULA
| a(n) = A024364(n)/2.
|
|
|
MAPLE
| isA020886 := proc(an) local r::integer, s::integer ; for r from floor((an/2)^(1/2)) to floor(an^(1/2)) do for s from r-1 to 1 by -2 do if r*(r+s) = an and gcd(r, s) < 2 then RETURN(true) ; fi ; if r*(r+s) < an then break ; fi ; od ; od : RETURN(false) ; end : for n from 2 to 400 do if isA020886(n) then printf("%d, ", n) ; fi ; od ; - R. J. Mathar (mathar(AT)strw.leidenuniv.nl), Jun 08 2006
|
|
|
CROSSREFS
| Cf. A020882-A020885.
Sequence in context: A045848 A044439 A128253 * A093508 A094183 A196394
Adjacent sequences: A020883 A020884 A020885 * A020887 A020888 A020889
|
|
|
KEYWORD
| nonn
|
|
|
AUTHOR
| Clark Kimberling (ck6(AT)evansville.edu)
|
| |
|
|
