

A274578


Nonsquare n such that n^3  1 is the average of two positive cubes.


0




OFFSET

1,1


COMMENTS

The equation x^3 + y^3 = 2*z^3 has no integer solution triple (x, y, z) for x > y and z is nonzero. So this sequence focuses on the equation x^3 + y^3 = 2*(z^3  1) where x, y > 0.


LINKS

Table of n, a(n) for n=1..8.


EXAMPLE

2305 is a term because it is not a square and 2305^3  1 = (144^3 + 2904^3) / 2.


PROG

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


CROSSREFS

Cf. A000037, A003325, A068601, A273822.
Sequence in context: A259321 A223302 A174558 * A031774 A031546 A250874
Adjacent sequences: A274575 A274576 A274577 * A274579 A274580 A274581


KEYWORD

nonn,more


AUTHOR

Altug Alkan, Jun 29 2016


STATUS

approved



