A025391 Numbers that are the sum of 4 distinct nonzero squares in 7 or more ways.

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

Offset

1,1

Links

Robert Israel, Table of n, a(n) for n = 1..10000

Index entries for sequences related to sums of squares

Formula

{n: A025443(n) >= 7}. - R. J. Mathar, Jun 15 2018

Maple

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

Mathematica

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 *)

Crossrefs

Cf. A025372.

Sequence in context: A119903 A113796 A127994 * A025382 A179518 A186076

Adjacent sequences: A025388 A025389 A025390 * A025392 A025393 A025394

Keyword

nonn

Author

David W. Wilson

Status

approved