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Numbers that are the sum of 4 distinct positive cubes in 2 or more ways.
2

%I #14 Oct 23 2023 16:14:57

%S 1036,1134,1352,1367,1430,1465,1484,1521,1547,1582,1638,1709,1736,

%T 1764,1800,1801,1820,1862,1863,1881,1918,1953,1972,2009,2070,2080,

%U 2099,2136,2197,2249,2268,2288,2305,2331,2340,2366,2422,2457,2464,2483,2485,2520

%N Numbers that are the sum of 4 distinct positive cubes in 2 or more ways.

%H Robert Israel, <a href="/A025412/b025412.txt">Table of n, a(n) for n = 1..10000</a>

%p M:= 4000: # for terms <= M

%p V:= Vector(M):

%p for a from 1 while 4*a^3 < M do

%p for b from a+1 while a^3 + 3*b^3 < M do

%p for c from b+1 while a^3 + b^3 + 2*c^3 < M do

%p for d from c+1 do

%p v:= a^3 + b^3 + c^3 + d^3;

%p if v > M then break fi;

%p V[v]:= V[v]+1

%p od od od od:

%p select(t -> V[t] > 1, [$1..M]); # _Robert Israel_, Oct 23 2023

%Y Cf. A025409, A025421.

%K nonn

%O 1,1

%A _David W. Wilson_