A352133 Centered cube numbers that can be written as sums of two other cubes in at least one way.

91, 189, 1729, 12691, 68705, 97309, 201159, 400491, 2484755, 2554741, 3587409, 3767491, 8741691, 15407765, 26122131, 54814509, 121861441, 139361059, 168632191, 223264809, 236019771, 295233841, 355957875, 448404255, 508476241, 525518721, 1041378589, 2593625571, 2746367559, 2874318841, 4328420941, 5193550999

Offset: 1

Author

Vladimir Pletser, Mar 05 2022

Keywords

• nonn

Comments

Numbers that are the sum of two consecutive cubes and at least one other sum of two cubes: a(n) = b(n)^3 + (b(n) + 1)^3 = c(n)^3 + d(n)^3, with c(n) > b(n) and c(n) > |d(n)|, and where b(n)=A352134(n), c(n)=A352135(n) and d(n)=A352136(n).

Subsequence of A005898.

Examples

			91 belongs to the sequence because 91 = 3^3 + 4^3 = 6^3 + (-5)^3.
		

Links

• Vladimir Pletser, Table of n, a(n) for n = 1..275
• A. Grinstein, Ramanujan and 1729, University of Melbourne Dept. of Math and Statistics Newsletter: Issue 3, 1998.
• Eric Weisstein's World of Mathematics, Centered Cube Number

Crossrefs

Cf. A005898, A001235, A272885, A352134, A352135, A352136, A352220, A352221, A352222, A352223, A352224, A352225.

Formula

a(n) = A352134(n)^3 + (A352134(n) + 1)^3 = A352135(n)^3 + A352136(n)^3.