A155961 Numbers whose square can be expressed as the sum of two positive cubes in at least 3 ways.

3343221000, 26745768000, 90266967000

Offset: 1

Author

Ray Chandler, Jan 31 2009

Keywords

• nonn
• hard
• more
• bref

Comments

Although this sequence has keyword "bref", this sequence is infinite since if n is in this sequence, then n*k^3 is in this sequence for all k > 0. - Altug Alkan, May 10 2016

Examples

			a(1)=3343221000 where 3343221000^2 = 279300^3 + 2234400^3 = 790020^3 + 2202480^3 = 1256850^3 + 2094750^3.
		

Links

• Uwe Hollerbach, Taxi, Taxi! [Original link, broken]
• Uwe Hollerbach, Taxi, Taxi! [Replacement link to Wayback Machine]
• Uwe Hollerbach, Taxi! Taxi! [Cached copy from Wayback Machine, html version of top page only]

Crossrefs

Cf. A051302, A155960.

Formula

a(n) = sqrt(A155960(n)).