A051388 Numbers whose 4th power can be expressed as the sum of two positive cubes in more than one way.

1729, 2457, 4104, 4914, 4977, 8001, 8216, 10773, 13832, 15561, 16263, 19656, 20683, 32832, 39312, 39816, 40033, 46683, 64008, 64232, 65728, 66339, 80236, 86184, 110656, 110808, 124336, 124488, 127062, 130104, 132678, 132867, 134379, 149389, 157248, 165464, 166887, 171288

Offset: 1

Author

Jud McCranie

Keywords

• nonn

Examples

			1729^4 = 1729^3 + 20748^3 = 15561^3 + 17290^3.
		

Links

• Chai Wah Wu, Table of n, a(n) for n = 1..358

Crossrefs

Cf. A051386, A051387.

Cf. A226777, A226950.

Programs

PARI

for(i=1, 10^5, x=i^4; c=0; for(j=1, floor(sqrtn(x/2,3)), if(ispower(x-j^3,3), c++)); if(c>1, print(i" "c))) \\ Donovan Johnson, Aug 03 2009

Extensions

More terms from John W. Layman, Feb 24 2003

a(18)-a(24) from Donovan Johnson, Aug 03 2009

a(25)-a(38) from Donovan Johnson, Dec 03 2010