cp's OEIS Frontend

A025412 Numbers that are the sum of 4 distinct positive cubes in 2 or more ways.

%I A025412 #14 Oct 23 2023 16:14:57
%S A025412 1036,1134,1352,1367,1430,1465,1484,1521,1547,1582,1638,1709,1736,
%T A025412 1764,1800,1801,1820,1862,1863,1881,1918,1953,1972,2009,2070,2080,
%U A025412 2099,2136,2197,2249,2268,2288,2305,2331,2340,2366,2422,2457,2464,2483,2485,2520
%N A025412 Numbers that are the sum of 4 distinct positive cubes in 2 or more ways.
%H A025412 Robert Israel, <a href="/A025412/b025412.txt">Table of n, a(n) for n = 1..10000</a>
%p A025412 M:= 4000: # for terms <= M
%p A025412 V:= Vector(M):
%p A025412 for a from 1 while 4*a^3 < M do
%p A025412   for b from a+1 while a^3 + 3*b^3 < M do
%p A025412     for c from b+1 while a^3 + b^3 + 2*c^3 < M do
%p A025412       for d from c+1 do
%p A025412         v:= a^3 + b^3 + c^3 + d^3;
%p A025412         if v > M then break fi;
%p A025412         V[v]:= V[v]+1
%p A025412 od od od od:
%p A025412 select(t -> V[t] > 1, [$1..M]); # _Robert Israel_, Oct 23 2023
%Y A025412 Cf. A025409, A025421.
%K A025412 nonn
%O A025412 1,1
%A A025412 _David W. Wilson_