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A056825
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Numbers such that no smaller positive integer has the same maximal palindrome in the periodic part of the simple continued fraction for its square root.
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2
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2, 3, 6, 7, 11, 13, 14, 18, 19, 21, 22, 23, 27, 28, 29, 31, 34, 38, 41, 43, 44, 45, 46, 47, 51, 52, 53, 54, 55, 57, 58, 59, 61, 62, 66, 67, 69, 70, 71, 73, 76, 77, 79, 83, 85, 86, 88, 89, 91, 92, 93, 94, 97, 98, 102, 103, 106, 107, 108, 109, 111, 113, 114, 115, 116, 117, 118, 119
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OFFSET
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1,1
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REFERENCES
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O. Perron, "Die Lehre von den Kettenbruechen, Bd.I", Teubner, 1954. (Sec. 26)
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LINKS
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EXAMPLE
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33, 60 and 95 are not in the list because their square roots' simple continued fractions, [5,1,2,1,10,1,2,1,10,...], [7,1,2,1,14,...] and [9,1,2,1,18,...], have the same maximal palindrome in their periods as the square root of 14, [3,1,2,1,6,1,2,1,6,...] does.
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PROG
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(Python)
from sympy.ntheory.continued_fraction import continued_fraction_periodic
A056825_list, nset, n = [], set(), 1
cf = continued_fraction_periodic(0, 1, n)
if len(cf) > 1:
pal = tuple(cf[1][:-1])
if pal not in nset:
nset.add(pal)
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CROSSREFS
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KEYWORD
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nonn
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AUTHOR
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EXTENSIONS
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Missing terms 108 and 117 added by Chai Wah Wu, Sep 13 2021
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STATUS
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approved
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