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A175376 Partial sums of A175375. 2
1, 7, 19, 27, 27, 27, 27, 27, 27, 27, 27, 27, 27, 27, 27, 27, 33, 57, 81, 81, 81, 81, 81, 81, 81, 81, 81, 81, 81, 81, 81, 81, 93, 117, 117, 117, 117, 117, 117, 117, 117, 117, 117, 117, 117, 117, 117, 117, 125, 125, 125, 125, 125, 125, 125, 125, 125, 125, 125, 125, 125 (list; graph; refs; listen; history; text; internal format)
OFFSET

0,2

COMMENTS

Number of integer triples (x,y,z) satisfying x^4+y^4+z^4 <= n, -n <= x,y,z <= n.

LINKS

Robert Israel, Table of n, a(n) for n = 0..10000

FORMULA

G.f.: (1 + 2*Sum_{j>0} x^(j^4))^3/(1-x). - Robert Israel, May 01 2019

MAPLE

N:= 100: # to get a(1)..a(N)

A:= Array(0..N):

for i from 0 while i^4 <= N do

  if i=0 then ai:= 1 else ai:= 2 fi;

  for j from 0 while i^4 + j^4 <= N do

    if j=0 then aj:= 1 else aj:= 2 fi;

    for k from 0 do

      v:= i^4 + j^4 + k^4;

      if v > N then break fi;

      if k = 0 then ak:= 1 else ak:= 2 fi;

      A[v]:= A[v] + ai*aj*ak;

od od od:

ListTools:-PartialSums(convert(A, list)); # Robert Israel, May 01 2019

CROSSREFS

Cf. A117609, A175366, A175375.

Sequence in context: A038593 A014439 A342160 * A175366 A117609 A122072

Adjacent sequences:  A175373 A175374 A175375 * A175377 A175378 A175379

KEYWORD

nonn

AUTHOR

R. J. Mathar, Apr 24 2010

STATUS

approved

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Last modified August 5 07:31 EDT 2021. Contains 346464 sequences. (Running on oeis4.)