

A271717


Integers n such that both n and n^31 are the sum of two positive cubes (see A003325).


0



9, 11664, 36864, 38134, 345744, 1750329, 4782969, 20820969, 47775744, 65804544, 95004009, 150994944, 448084224, 733055625, 1093955625, 1416167424
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OFFSET

1,1


COMMENTS

Values of a^3 + b^3 such that (a^3 + b^3)^3  1 is of the form x^3 + y^3 where a, b, x, y > 0.
38134 = 2*23*829 is the first term that is nonsquare. What are the next square terms of this sequence?
n is a member of A007412 and n^3 is a member of A003072, obviously.


LINKS

Table of n, a(n) for n=1..16.


EXAMPLE

9 is a term because 9 = 1^3 + 2^3 and 9^3  1 = 6^3 + 8^3.


PROG

(PARI) isA003325(n) = for(k=1, sqrtnint(n\2, 3), ispower(nk^3, 3) && return(1));
for(n=1, 1e7, if(isA003325(n) && isA003325(n^31), print1(n, ", ")));


CROSSREFS

Cf. A003325, A050787, A068601.
Sequence in context: A175987 A321618 A055320 * A069501 A030254 A206461
Adjacent sequences: A271714 A271715 A271716 * A271718 A271719 A271720


KEYWORD

nonn,more


AUTHOR

Altug Alkan, Apr 12 2016


EXTENSIONS

a(8)a(16) from Chai Wah Wu, Apr 17 2016


STATUS

approved



