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A018850 Numbers that are the sum of 2 cubes in more than 1 way (primitive solutions). 4
1729, 4104, 20683, 39312, 40033, 64232, 65728, 134379, 149389, 171288, 195841, 216027, 327763, 402597, 439101, 443889, 515375, 684019, 704977, 805688, 842751, 920673, 955016, 984067, 994688, 1009736, 1016496, 1073375, 1092728, 1331064 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

COMMENTS

Nakao's table has more entries because he lists nonprimitive numbers if they are the sum of two cubes in three ways.

Rajesh Bhowmick, Dec 12 2011: The odd number 40533595075161 can be represented as sum of two cubes in just two different ways: (34314)^(3)+(5073)^(3)=(34321)^(3)+(4730)^(3). Here the cubes are greater than 1, there is no common factor between the odd numbers, there is no common factor between the L.H.S & the R.H.S, the even number is greater than 2, the cubes are in their primitive form, and they are not of the form (27)^(3) or (121)^(3) (which are actually (3)^(9) & (11)^(6)).

LINKS

T. D. Noe, Table of n, a(n) for n = 1..1694

H. Nakao, Ramanujan Taxi Numbers [1...1000000000]

Eric Weisstein's World of Mathematics, Cubic Number

CROSSREFS

Cf. A001235.

Sequence in context: A138129 A242880 A001235 * A062924 A130859 A245671

Adjacent sequences:  A018847 A018848 A018849 * A018851 A018852 A018853

KEYWORD

nonn

AUTHOR

David W. Wilson

STATUS

approved

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Last modified July 15 14:53 EDT 2019. Contains 325031 sequences. (Running on oeis4.)