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A251411
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Numbers n such that A098550(n) = n.
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3
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OFFSET
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1,2
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COMMENTS
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There is a strong conjecture that there are no further terms. See the discussion in the comments in A098550.
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REFERENCES
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L. Edson Jeffery, Posting to Sequence Fans Mailing List, Nov 30 2014.
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LINKS
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MATHEMATICA
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max = 100;
f[lst_] := Block[{k = 4}, While[GCD[lst[[-2]], k] == 1 || GCD[lst[[-1]], k] > 1 || MemberQ[lst, k], k++]; Append[lst, k]];
A098550 = Nest[f, {1, 2, 3}, max - 3];
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PROG
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(Python)
from fractions import gcd
A251411_list, l1, l2, s, b = [1, 2, 3], 3, 2, 4, {}
for n in range(4, 10**4):
....i = s
....while True:
........if not i in b and gcd(i, l1) == 1 and gcd(i, l2) > 1:
............l2, l1, b[i] = l1, i, 1
............while s in b:
................b.pop(s)
................s += 1
............if i == n:
................A251411_list.append(n)
............break
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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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