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A025343
Numbers that are the sum of 3 distinct nonzero squares in exactly 5 ways.
1
206, 230, 266, 269, 326, 350, 381, 389, 398, 413, 414, 425, 437, 441, 470, 474, 486, 525, 554, 585, 590, 593, 611, 630, 635, 638, 659, 662, 674, 706, 729, 731, 758, 781, 819, 824, 829, 830, 851, 874, 878, 890, 901, 905, 917, 920, 923, 978, 985, 1006, 1011, 1021, 1035
OFFSET
1,1
MAPLE
N:= 10^6;
A:= Vector(N):
for a from 1 to floor(sqrt(N/3)) do
for b from a+1 to floor(sqrt((N-a^2)/2)) do
c:= [$(b+1) .. floor(sqrt(N-a^2-b^2))]:
v:= map(t -> a^2 + b^2 + t^2, c):
A[v]:= map(`+`, A[v], 1)
od od:
select(t -> A[t]=5, [$1..N]); # Robert Israel, Jan 03 2016
CROSSREFS
Sequence in context: A261749 A058180 A025351 * A222619 A252270 A113934
KEYWORD
nonn
STATUS
approved