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A240562
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Integers whose squares are in A000073 (tribonacci numbers).
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0
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OFFSET
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1,3
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COMMENTS
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Is this sequence finite?
No more terms < 10^19300. I conjecture that the sequence is finite. - Manfred Scheucher, Aug 17 2015
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LINKS
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EXAMPLE
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9^2 = 81 is in the tribonacci sequence, so 9 is a term.
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MATHEMATICA
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Select[Sqrt[#]&/@LinearRecurrence[{1, 1, 1}, {0, 0, 1}, 200], IntegerQ]// Union (* Harvey P. Dale, Aug 16 2021 *)
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PROG
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(Sage)
def tribs():
a, b, c = 0, 0, 1
while True:
yield a
a, b, c = b, c, a+b+c
for n in tribs():
m = sqrt(n)
if m.is_integer():
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CROSSREFS
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Cf. A000073 (tribonacci numbers), A128911 (the corresponding squares).
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KEYWORD
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nonn,more,hard
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AUTHOR
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EXTENSIONS
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STATUS
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approved
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