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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

Shahar Amitai, Table of n, a(n) for n = 1..9859 (terms a(1)-a(1694) from T. D. Noe).

Shahar Amitai, Python code to generate all primitive taxicab numbers up to N.

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

Eric Weisstein's World of Mathematics, Cubic Number

CROSSREFS

Cf. A001235.

Sequence in context: A242880 A001235 A343708 * 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 May 14 06:35 EDT 2021. Contains 343879 sequences. (Running on oeis4.)