|
Search: id:A051388
|
|
|
| A051388 |
|
Numbers whose 4th power can be expressed as the sum of two positive cubes in more than one way. |
|
+0
1
|
|
| 1729, 2457, 4104, 4914, 4977, 8001, 8216, 10773, 13832, 15561, 16263, 19656, 20683, 32832, 39312, 39816, 40033, 46683, 64008, 64232, 65728, 66339, 80236, 86184
(list; graph; listen)
|
|
|
OFFSET
|
1,1
|
|
|
COMMENT
|
a(25) > 10^5. [From Donovan Johnson (donovan.johnson(AT)yahoo.com), Aug 03 2009]
|
|
EXAMPLE
|
1729^4 = 1729^3+20748^3 = 15561^3+17290^3
|
|
PROGRAM
|
(PARI) for(i=1, 10^5, x=i^4; c=0; for(j=1, floor(sqrtn(x/2, 3)), if(ispower(x-j^3, 3), c++)); if(c>1, print(i" "c))) [From Donovan Johnson (donovan.johnson(AT)yahoo.com), Aug 03 2009]
|
|
CROSSREFS
|
Cf. A051386, A051387.
Sequence in context: A112140 A044883 A154717 this_sequence A033181 A154729 A083737
Adjacent sequences: A051385 A051386 A051387 this_sequence A051389 A051390 A051391
|
|
KEYWORD
|
more,nonn
|
|
AUTHOR
|
Jud McCranie (j.mccranie(AT)comcast.net)
|
|
EXTENSIONS
|
More terms from John W. Layman (layman(AT)math.vt.edu), Feb 24 2003
a(18)-a(24) from Donovan Johnson (donovan.johnson(AT)yahoo.com), Aug 03 2009
|
|
|
Search completed in 0.002 seconds
|
