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A059591
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Squarefree part of n^2+1.
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5
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1, 2, 5, 10, 17, 26, 37, 2, 65, 82, 101, 122, 145, 170, 197, 226, 257, 290, 13, 362, 401, 442, 485, 530, 577, 626, 677, 730, 785, 842, 901, 962, 41, 1090, 1157, 1226, 1297, 1370, 5, 1522, 1601, 2, 1765, 74, 1937, 2026, 2117, 2210, 2305, 2402, 2501, 2602
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OFFSET
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0,2
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COMMENTS
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Related to period-1 continued fractions [z,z,z,...].
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LINKS
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FORMULA
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EXAMPLE
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a(7)=2 since 7^2+1 = 50 = 25*2 = (5^2)*2.
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MAPLE
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A:= proc(n)
local F;
F:= select(t -> t[2]::odd, ifactors(n^2+1)[2]);
mul(t[1], t=F)
end proc:
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MATHEMATICA
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Table[Times @@ Flatten[Table[#1, {#2}] & @@@ Select[FactorInteger[n^2 + 1], OddQ@ Last@ # &]], {n, 120}] (* Michael De Vlieger, Jun 19 2015 *)
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PROG
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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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