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A046895
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Sizes of successive clusters in Z^4 lattice.
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6
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1, 9, 33, 65, 89, 137, 233, 297, 321, 425, 569, 665, 761, 873, 1065, 1257, 1281, 1425, 1737, 1897, 2041, 2297, 2585, 2777, 2873, 3121, 3457, 3777, 3969, 4209, 4785, 5041, 5065, 5449, 5881, 6265, 6577, 6881, 7361, 7809, 7953, 8289, 9057
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OFFSET
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0,2
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COMMENTS
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Number of lattice points inside or on the 4-sphere x^2+y^2+z^2+u^2=n. - T. D. Noe, Mar 14 2009
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LINKS
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T. D. Noe, Table of n, a(n) for n = 0..1000
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FORMULA
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a(n) = A122510(4,n). a(n^2)=A055410(n). [R. J. Mathar, Apr 21 2010]
G.f.: T3(q)^4/(1-q) where T3(q) = 1 + 2*sum(k>=1, q^(k^2) ). [Joerg Arndt, Apr 08 2013]
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MATHEMATICA
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Accumulate[ Table[ SquaresR[4, n], {n, 0, 42}]](* Jean-François Alcover, May 11 2012 *)
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PROG
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(PARI)
q='q+O('q^66);
Vec((eta(q^2)^5/(eta(q)^2*eta(q^4)^2))^4/(1-q))
/* Joerg Arndt, Apr 08 2013 */
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CROSSREFS
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Partial sums of A000118.
Cf. A117609
Sequence in context: A146262 A161430 A175369 * A165392 A145923 A092562
Adjacent sequences: A046892 A046893 A046894 * A046896 A046897 A046898
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KEYWORD
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nonn,easy,nice
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AUTHOR
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N. J. A. Sloane.
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STATUS
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approved
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