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

 

Logo


Hints
(Greetings from The On-Line Encyclopedia of Integer Sequences!)
A025398 Numbers that are the sum of 3 positive cubes in 3 or more ways. 3
5104, 9729, 12104, 12221, 12384, 13896, 14175, 17604, 17928, 19034, 20691, 21412, 21888, 24480, 28792, 29457, 30528, 31221, 32850, 34497, 35216, 36288, 38259, 39339, 39376, 40041, 40060, 40097, 40832, 40851, 41033, 41040, 41364, 41966, 42056, 42687 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

LINKS

Donovan Johnson, Table of n, a(n) for n = 1..10000

FORMULA

A008917(n) < a(n) <= A025397(n). - Jonathan Sondow, Oct 24 2013

EXAMPLE

a(1) = A230477(3) = 5104 = 1^3 + 12^3 + 15^3 = 2^3 + 10^3 + 16^3 = 9^3 + 10^3 + 15^3. - Jonathan Sondow, Oct 24 2013

MATHEMATICA

Select[ Range[ 50000], 2 < Length @ Cases[ PowersRepresentations[#, 3, 3], {_?Positive, _?Positive, _?Positive}] &] (* adapted from Alcover's program for A008917 by Jonathan Sondow, Oct 24 2013 *)

PROG

(PARI) is(n)=k=ceil((n-2)^(1/3)); d=0; for(a=1, k, for(b=a, k, for(c=b, k, if(a^3+b^3+c^3==n, d++)))); d

n=3; while(n<50000, if(is(n)>=3, print1(n, ", ")); n++) \\ Derek Orr, Aug 27 2015

CROSSREFS

Cf. A008917, A025397, A230477.

Sequence in context: A135842 A224492 A219329 * A025397 A025402 A025401

Adjacent sequences:  A025395 A025396 A025397 * A025399 A025400 A025401

KEYWORD

nonn

AUTHOR

David W. Wilson

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 | More pages
The OEIS Community | Maintained by The OEIS Foundation Inc.

License Agreements, Terms of Use, Privacy Policy .

Last modified June 26 13:33 EDT 2017. Contains 288766 sequences.