The OEIS is supported by the many generous donors to the OEIS Foundation. Hints (Greetings from The On-Line Encyclopedia of Integer Sequences!)
 A051386 Numbers whose 4th power is the sum of two positive cubes. 3
 2, 9, 16, 28, 35, 54, 65, 72, 91, 126, 128, 133, 134, 152, 182, 183, 189, 201, 217, 219, 224, 243, 250, 273, 278, 280, 309, 341, 344, 351, 370, 399, 407, 422, 432, 453, 468, 497, 513, 520, 539, 559, 576, 579, 637, 651, 658, 686, 728, 730, 737, 756, 793, 854 (list; graph; refs; listen; history; text; internal format)
 OFFSET 1,1 COMMENTS n such that n^4 = r^3 + s^3 has a solution with r>0, s>0. By multiplying n^4 = r^3 + s^3 by n^3, also numbers whose 7th power is expressible as the sum of positive cubes. When n is the sum of 2 positive cubes (A003325) there is a trivial solution: e.g., 133 is a term in A003325, 133=2^3+5^3 and 133^4=(2*133)^3+(5*133)^3. - Zak Seidov, Oct 17 2011 From Robert Israel, Jun 01 2015: (Start) Slightly more generally, if x^3 + y^3 = u*v^4, then (u*v*w^3)^4 = (u*w^4*x)^3 + (u*w^4*y)^3, so u*v*w^3 is in the sequence for any w >= 1. There are at least five pairs of adjacent numbers in the sequence: (133,134),(182,183), (854,855), (1842,1843), (3473,3474). Are there infinitely many? (End) LINKS Chai Wah Wu, Table of n, a(n) for n = 1..10000 EXAMPLE 134^4 = 469^3 + 603^3. MAPLE N:= 1000: # to get all terms <= N Cubes:= {seq(x^3, x=1..floor(N^(4/3)))}: select(n -> nops(map(t -> n^4-t, Cubes) intersect Cubes)>0, [\$1..N]); # Robert Israel, Jun 01 2015 CROSSREFS Cf. A003325, A051387. Sequence in context: A288484 A011193 A085960 * A003325 A338667 A101420 Adjacent sequences: A051383 A051384 A051385 * A051387 A051388 A051389 KEYWORD nonn AUTHOR Jud McCranie STATUS approved

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

Last modified September 24 00:14 EDT 2023. Contains 365554 sequences. (Running on oeis4.)