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A295576
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a(n) = Sum_{1 <= j <= n/2, gcd(j,n)=1} j^4.
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3
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0, 1, 1, 1, 17, 1, 98, 82, 273, 82, 979, 626, 2275, 707, 2674, 3108, 8772, 3027, 15333, 9044, 14994, 9669, 39974, 17668, 50085, 24310, 60597, 50470, 127687, 45604, 178312, 103496, 149908, 103496, 225302, 129750, 432345, 187017, 349830, 266088, 722666
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OFFSET
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1,5
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COMMENTS
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If p is an odd prime, a(p) = p*(p^2-1)*(3*p^2-7)/480. - Robert Israel, Dec 10 2017
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LINKS
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MAPLE
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f:= n -> add(t^4, t = select(t->igcd(t, n)=1, [$1..n/2])):
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MATHEMATICA
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f[n_] := Plus @@ (Select[Range[n/2], GCD[#, n] == 1 &]^4); Array[f, 41] (* Robert G. Wilson v, Dec 10 2017 *)
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PROG
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(PARI) a(n) = sum(j=1, n\2, (gcd(j, n)==1)*j^4); \\ Michel Marcus, Dec 10 2017
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CROSSREFS
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In the Baum (1982) paper, S_1, S_2, S_3, S_4 are A023896, A053818, A053819, A053820, and S'_1, S'_2, S'_3, S'_4 are A066840, A295574, A295575, A295576.
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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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