A293648 Sum of two (possibly negative) coprime cubes in at least 2 ways, but not the sum of 2 noncoprime cubes.

91, 217, 721, 1027, 1729, 3367, 4706, 4921, 4977, 7657, 8587, 8911, 9919, 10621, 14911, 15561, 16263, 20683, 21014, 23877, 25669, 27937, 28063, 31519, 35929, 39331, 40033, 49959, 63693, 68705, 68857, 68913, 73017, 77653, 77779, 97309, 98623, 106597, 109573

Offset: 1

Author

Rosalie Fay, Oct 16 2017

Keywords

• nonn

Comments

Not every term is cubefree; some are sb^3 where s is in A159843 and b > 1.

Examples

			63693 = 34^3 + 29^3 = 53^3 - 44^3 and 34 & 29 are coprime, as are 53 & -44, but it is not also the sum of cubes of 2 noncoprime integers, so 63693 is in the sequence.
		

Links

• Rosalie Fay, Table of n, a(n) for n = 1..325

Crossrefs

Cf. A293647 (allows noncoprime); A293649 (only positives); A293646, A293651