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A025391
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Numbers that are the sum of 4 distinct nonzero squares in 7 or more ways.
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2
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190, 198, 210, 222, 231, 238, 246, 255, 270, 282, 286, 290, 294, 302, 303, 306, 310, 315, 318, 326, 330, 334, 335, 338, 342, 345, 350, 351, 354, 357, 358, 363, 366, 369, 370, 374, 375, 378, 381, 382, 385, 386, 387, 390, 393, 394, 398, 399, 402, 405, 406, 407, 410, 411
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OFFSET
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1,1
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LINKS
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FORMULA
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MAPLE
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N:= 1000: # for terms <= N
G:= mul(1+x^(i^2)*y, i=1..floor(sqrt(N))):
G4:= series(coeff(G, y, 4), x, N+1):
A:= select(t -> coeff(G4, x, t) >= 7, [$1..N]); # Robert Israel, Nov 19 2023
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MATHEMATICA
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With[{nn=25}, Select[Select[Tally[Total/@Subsets[Range[nn]^2, {4}]], #[[2]]> 6&][[All, 1]]//Union, #<=(nn^2-14)&]] (* Harvey P. Dale, Jun 21 2021 *)
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CROSSREFS
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KEYWORD
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nonn
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AUTHOR
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STATUS
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approved
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