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A284760
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a(n) = Sum_{i=1..n-1}(i^(n-2)) mod n^4.
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2
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0, 1, 3, 14, 100, 979, 196, 500, 3834, 1333, 2178, 1022, 16731, 12647, 42420, 23912, 23409, 26265, 15162, 79730, 84441, 21723, 28566, 160732, 280625, 329405, 137295, 569702, 74849, 71999, 463202, 715984, 247665, 31873, 1302420, 574170, 807710, 225091, 1377129
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OFFSET
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1,3
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COMMENTS
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Mestrovic conjectures that a(n) > 0 for all n > 1 (Conjecture 2.11).
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LINKS
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FORMULA
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EXAMPLE
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For n=5 the sum is 1^3 + 2^3 + 3^3 + 4^3 = 1 + 8 + 27 + 64 = 100; the modulus is 5^4 = 625. So a(5) = 100 mod 625 = 100. - Peter Munn, May 01 2017
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MATHEMATICA
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Table[Mod[Sum[i^(n - 2), {i, n - 1}], n^4], {n, 39}] (* Michael De Vlieger, Apr 05 2017 *)
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PROG
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(PARI) a(n) = lift(Mod(sum(i=1, n-1, i^(n-2)), n^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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