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Search: id:A098894
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| A098894 |
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Values of n such that {s(1),...,s(n)} is a palindrome, where {s(1),s(2),...} is the fixed-point of the substitutions 0->1 and 1->110. |
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+0
1
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| 1, 2, 5, 8, 15, 22, 39, 56, 97, 138, 237, 336, 575, 814, 1391, 1968, 3361, 4754, 8117, 11480, 19599, 27718, 47319, 66920, 114241, 161562, 275805, 390048, 665855, 941662, 1607519, 2273376, 3880897, 5488418, 9369317
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OFFSET
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1,2
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COMMENT
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Superseeker suggests: (1) ogf (1+x+x^2+x^3)/(1+2x-2x^2-x^3+x^4+x^5), (2) terms of odd index {1,5,15,39,...} give A034182, and (3) {a(n)+2} gives A082766, except for several initial terms.
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EXAMPLE
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Start with 1 and iterate the substitutions 0->1, 1->110 to get 1, 110, 1101101, 11011011101101110, 11011011101101110110110111011011101101101,... The initial terms from the beginning to the single quotes form palindromes: 1'1'011'011'1011011'1011011',..., of lengths 1,2,5,8,15,22,...
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CROSSREFS
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Cf. A034182, A082766.
Sequence in context: A090980 A024808 A077866 this_sequence A121641 A058884 A073335
Adjacent sequences: A098891 A098892 A098893 this_sequence A098895 A098896 A098897
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KEYWORD
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nonn
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AUTHOR
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John W. Layman (layman(AT)math.vt.edu), Nov 04 2004
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