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

1,1

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.

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

Formula

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

Example

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

Crossrefs

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

Sequence in context: A037998 A063367 A064904 * A044423 A044804 A211443

Adjacent sequences: A352130 A352131 A352132 * A352134 A352135 A352136

Keyword

nonn

Author

Vladimir Pletser, Mar 05 2022

Status

approved