1,3

Numbers n such that n! = x^2 + y^3 where x, y are integers and y >= 0, is soluble.

a(7) > 33. - Giovanni Resta, Jun 03 2016

Table of n, a(n) for n=1..6.

4 is a term because 4! = 4^2 + 2^3.

19 is a term because 19! = 345427200^2 + 132480^3.

21 is a term because 21! = 6389296200^2 + 2173500^3.

Cf. A000142, A022549.

Sequence in context: A275000 A290595 A009418 * A153691 A184308 A268338

Adjacent sequences: A273550 A273551 A273552 * A273554 A273555 A273556

nonn,more

Altug Alkan, May 25 2016

approved