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A352133 Centered cube numbers that can be written as sums of two other cubes in at least one way. 18
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 (list; graph; refs; listen; history; text; internal format)
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
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
Sequence in context: A037998 A063367 A064904 * A044423 A044804 A211443
KEYWORD
nonn
AUTHOR
Vladimir Pletser, Mar 05 2022
STATUS
approved

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Last modified April 17 08:54 EDT 2024. Contains 371763 sequences. (Running on oeis4.)