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A295391
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a(1) = 2; a(n+1) = 1 + (a(n)^2 - a(n))*(1+1/n) for n >= 1.
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1
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2, 5, 31, 1241, 1923551, 4440055831261, 22999778415495431257188671, 604559779613588034852176053517136070371409409780081, 411179093017233901729922229390651516928263091167446329166300037456998815010841080003014976133796409791
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OFFSET
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1,1
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COMMENTS
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(a(1), ..., a(n-1), a(n)-1) is an integer solution to the equation Sum_{k=1}^n k/x(k) = 1.
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LINKS
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EXAMPLE
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1/1 = 1.
1/2 + 2/4 = 1.
1/2 + 2/5 + 3/30 = 1.
1/2 + 2/5 + 3/31 + 4/1240 = 1.
1/2 + 2/5 + 3/31 + 4/1241 + 5/1923550 = 1.
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MAPLE
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a[1]:= 2:
for n from 1 to 10 do a[n+1]:= 1 + (a[n]^2 - a[n])*(1+1/n) od:
seq(a[i], i=1..11);
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MATHEMATICA
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Fold[Append[#1, 1 + (Last[#1]^2 - Last[#1]) (1 + 1/#2)] &, {2}, Range@ 8] (* Michael De Vlieger, Nov 21 2017 *)
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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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