login
This site is supported by donations to The OEIS Foundation.

 

Logo


Hints
(Greetings from The On-Line Encyclopedia of Integer Sequences!)
A051394 Numbers whose 5th power is expressible as the sum of two positive cubes. 1
3, 4, 24, 32, 81, 98, 108, 168, 192, 228, 256, 312, 375, 500, 525, 588, 648, 671, 784, 847, 864, 1014, 1029, 1183, 1225, 1261, 1323, 1344, 1372, 1536, 1824, 2048, 2187, 2496, 2646, 2888, 2916, 3000, 3549, 3993, 4000, 4200, 4225, 4536, 4563, 4644, 4704, 4914, 5054, 5184, 5324, 5368 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

COMMENTS

Every term z of A050801 is a term of this sequence: z^2 = x^3 + y^3, so z^2*z^3 = z^5 = (z*x)^3 + (z*y)^3.  Are there any terms that are not in A050801? [Joerg Arndt, Sep 30 2012]

The number 3549 is in this sequence but not in A050801, so the two sequences are distinct. - Eric M. Schmidt, Oct 29 2013

LINKS

Chai Wah Wu, Table of n, a(n) for n = 1..1000 (terms for n <= 185 from Donovan Johnson)

EXAMPLE

24^5 = 96^3 + 192^3.

PROG

(PARI) mm=1645714; cb=vector(mm); for(i=1, mm, cb[i]=i^3); j=2; for(n=2, 5368, p5=n^5; while(cb[j]<p5, j++); j1=1; j2=j; for(m=1, mm, if(j1>j2, next(2)); s=cb[j1]+cb[j2]; if(s<p5, j1++; next, if(s>p5, j2--; next); print1(n ", "); next(2)))) \\ Donovan Johnson, Oct 31 2013

CROSSREFS

Cf. A050801.

Sequence in context: A223526 A032831 A047180 * A050801 A103093 A124632

Adjacent sequences:  A051391 A051392 A051393 * A051395 A051396 A051397

KEYWORD

nonn

AUTHOR

Jud McCranie

EXTENSIONS

Sequence corrected and extended by Jonathan Sondow, Oct 28 2013

Corrected by Donovan Johnson, Oct 29 2013

STATUS

approved

Lookup | Welcome | Wiki | Register | Music | Plot 2 | Demos | Index | Browse | More | WebCam
Contribute new seq. or comment | Format | Style Sheet | Transforms | Superseeker | Recent
The OEIS Community | Maintained by The OEIS Foundation Inc.

License Agreements, Terms of Use, Privacy Policy. .

Last modified August 19 08:08 EDT 2019. Contains 326115 sequences. (Running on oeis4.)