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A347803
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Expansion of ( Sum_{k>=0} k^2 * q^(k^2) )^4.
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3
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0, 0, 0, 0, 1, 0, 0, 16, 0, 0, 96, 0, 36, 256, 0, 432, 256, 0, 1728, 64, 486, 2304, 768, 3888, 0, 3072, 7776, 1728, 7112, 0, 13824, 12864, 0, 27648, 6336, 15552, 9261, 18688, 62208, 21744, 24576, 0, 72576, 51456, 24300, 117504, 38400, 101088, 9216, 93184, 155520, 86400, 142382, 62208, 352512, 67344, 0, 202752, 286176
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OFFSET
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0,8
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LINKS
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FORMULA
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a(n) is sum of i^2 * j^2 * k^2 *m^2 for positive integers i,j,k,m such that i^2+j^2+k^2+m^2=n.
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PROG
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(PARI) a(n) = sum(i=1, n, sum(j=1, n, sum(k=1, n, sum(m=1, n, (i^2+j^2+k^2+m^2==n)*(i*j*k*m)^2))));
(PARI) my(N=66, x='x+O('x^N)); concat([0, 0, 0, 0], Vec(sum(k=0, sqrtint(N), k^2*x^k^2)^4))
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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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