A273546 Integers n such that n^n is the average of a nonzero square and a positive cube.

0, 1, 4, 6, 8, 9, 12, 13, 14, 18, 24, 25

Offset

1,3

Comments

Integers n such that n^n = (x^2 + y^3)/2 where x, y > 0, is soluble.

Links

Table of n, a(n) for n=1..12.

Example

13 is a term because 13^13 = (24134045^2 + 28561^3)/2.

Prog

(PARI) isA055394(n)=for(k=1, sqrtnint(n-1, 3), if(issquare(n-k^3), return(1))); 0
is(n)=isA055394(2*n^n) \\ Charles R Greathouse IV, Jun 08 2016

Crossrefs

Cf. A000312, A055394, A267415.

Sequence in context: A068631 A338461 A163520 * A176539 A285256 A013920

Adjacent sequences: A273543 A273544 A273545 * A273547 A273548 A273549

Keyword

nonn,more

Author

Altug Alkan, May 26 2016

Extensions

a(10)-a(12) from Giovanni Resta, May 26 2016

Status

approved