A352220 Centered cube numbers that can be written as sums of two other cubes in at least two ways.

3587409, 8741691, 26122131, 355957875, 2593625571, 2746367559, 70607389041, 367954598375, 7006302268875, 7916366521691, 8091803325879, 28332679374909, 144757538551899, 1026401875608375, 9339629571431315, 14295468330521189, 49873257556492139, 42892025638971003759

Offset

1,1

Comments

Numbers A such that A = B^3 + (B+1)^3 = C^3 + D^3 = E^3 + F^3 with C <> (D +- 1), E <> (F +- 1), E > C > B, C > |D| and E > |F|, where A = a(n) (this sequence), B = A352221(n), C = A352222(n), D = A352223(n), E = A352224(n) and F = A352225(n).

Subsequence of A005898 and of A352133.

Links

Table of n, a(n) for n=1..18.

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) = A352221(n)^3 + (A352221(n) + 1)^3 = A352222(n)^3 + A352223(n)^3 = A352224(n)^3 + A352225(n)^3.

Example

3587409 belongs to the sequence because 3587409 = 121^3 + 122^3 = 153^3 + 18^3 = 369^3 + (-360)^3.

Crossrefs

Cf. A005898, A001235, A272885, A352133, A352134, A352135, A352136, A352221, A352222, A352223, A352224, A352225.

Sequence in context: A209911 A235077 A353221 * A214173 A183970 A251305

Adjacent sequences: A352217 A352218 A352219 * A352221 A352222 A352223

Keyword

nonn

Author

Vladimir Pletser, Mar 07 2022

Extensions

a(6)-a(18) from Jon E. Schoenfield, Mar 09 2022

Status

approved