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A095238
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a(1) = 1, a(n) = n*(sum of all previous terms mod n).
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1
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1, 2, 0, 12, 0, 18, 35, 32, 9, 90, 11, 72, 117, 98, 30, 240, 34, 162, 247, 200, 63, 462, 69, 288, 425, 338, 108, 756, 116, 450, 651, 512, 165, 1122, 175, 648, 925, 722, 234, 1560, 246, 882, 1247, 968, 315, 2070, 329, 1152, 1617, 1250, 408, 2652, 424, 1458, 2035
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OFFSET
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1,2
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COMMENTS
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An open question is whether the sequence contains zeros except for the 3rd and the 5th number. I checked this up to a(10000), which happens to be 99990000. - Johan Claes, Jun 16 2004
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LINKS
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FORMULA
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Appears to satisfy a linear recurrence with characteristic polynomial (1+x)(1+x^3)^2(1-x^3)^3 (checked up to n = 10^4). - Ralf Stephan, Dec 04 2004
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EXAMPLE
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a(6) = 6*((1 + 2 + 0 + 12 + 0) mod 6) = 18.
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MAPLE
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MATHEMATICA
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a[1] = 1; a[n_] := a[n] = n*Mod[Sum[a[i], {i, n - 1}], n]; Table[ a[n], {n, 55}] (* Robert G. Wilson v, Jun 16 2004 *)
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PROG
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(PARI) a=vector(1000); a[1]=1; for(i=2, 1000, a[i]=i*lift(Mod(sum(j=1, i-1, a[j]), i)))
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CROSSREFS
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KEYWORD
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nonn
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AUTHOR
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EXTENSIONS
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STATUS
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approved
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