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A071932
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a(n) = 4*Sum_{i=1..n} K(i,i+1) - n, where K(x,y) is the Kronecker symbol (x/y).
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3
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1, 4, 7, 2, 5, 8, 11, 6, 1, 4, 7, 2, 5, 8, 11, 6, 9, 12, 15, 10, 5, 8, 11, 6, 1, 4, 7, 2, 5, 8, 11, 6, 9, 12, 15, 10, 13, 16, 19, 14, 9, 12, 15, 10, 5, 8, 11, 6, 9, 12, 15, 10, 5, 8, 11, 6, 1, 4, 7, 2, 5, 8, 11, 6, 9, 12, 15, 10, 13, 16, 19, 14, 9, 12, 15, 10, 13, 16, 19, 14, 17, 20, 23
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OFFSET
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3,2
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COMMENTS
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a(n) > 0 for n > 2 and it seems that a(n)/log(n) is bounded: a(n) < 4*log(n) for n sufficiently large. Does lim_{n->infinity} a(n)/log(n) exist?
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LINKS
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MATHEMATICA
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Table[4*Sum[KroneckerSymbol[j, j+1], {j, n}] - n, {n, 3, 80}] (* G. C. Greubel, Mar 17 2019 *)
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PROG
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(PARI) for(n=3, 100, print1(4*sum(i=1, n, kronecker(i, i+1))-n, ", "))
(Sage) [4*sum(kronecker_symbol(j+1, j) for j in (1..n))-n for n in (3..80)] # G. C. Greubel, Mar 17 2019
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CROSSREFS
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KEYWORD
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easy,nonn
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AUTHOR
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STATUS
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approved
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