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A057159
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Numbers k that divide s(k-1), where s(1) = 1, s(k) = s(k-1) + (k+1)*3^k.
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1
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4, 13, 35, 52, 95, 119, 169, 676, 11596, 57577, 159484, 276773, 360139, 1345747, 56193997, 60640957, 604170268, 807129973
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OFFSET
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1,1
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COMMENTS
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{s(n)} = {1, 28, 136, 541, 1999, 7102, 24598, ...}; 4*s(n) = 3^(n+1)*(2n+1) - 23, with g.f. x*(-1-21*x+45*x^2) / ( (x-1)*(-1+3*x)^2 ). - R. J. Mathar, May 05 2018
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LINKS
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MATHEMATICA
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seq = RecurrenceTable[{s[n] == s[n - 1] + (n + 1)*3^n, s[1] == 1}, s, {n, 1, 20000}]; Select[Range[1, Length[seq]], Divisible[seq[[# - 1]], #] &] (* Vaclav Kotesovec, May 05 2018 *)
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CROSSREFS
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KEYWORD
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nonn,more
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AUTHOR
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EXTENSIONS
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STATUS
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approved
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