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A064568
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n-th term in Recamán's sequence A005132 is divisible by n.
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4
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1, 3, 11, 21, 39, 76, 248, 844, 1520, 2752, 9317, 17223, 31221, 57071, 99741, 589932, 58056875, 101769229, 302890748, 511561220, 904036924, 39488697700, 325374626148
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OFFSET
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1,2
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COMMENTS
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LINKS
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EXAMPLE
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A005132(21) = 63, 63 is divisible by 21, so 21 is in the sequence.
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MATHEMATICA
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With[{s = Nest[Append[#1, If[And[#3 > 0, FreeQ[#1, #3]], #3, #1[[-1]] + #2]] & @@ {#1, #2, #1[[-1]] - #2} & @@ {#, Length@ #} &, {0}, 10^5]}, Reap[Do[If[Mod[s[[i]], i] == 0, Sow[i]], {i, Length@ s - 1}]][[-1, -1]]] (* Michael De Vlieger, Dec 29 2019 *)
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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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Offset changed, a(1), a(22)-a(23) from Jud McCranie, Dec 29 2019
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STATUS
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approved
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