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A062129
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In base 2: start with n; add to itself with digits reversed; if palindrome, stop; otherwise repeat; a(n) gives palindrome at which it stops, or -1 if no palindrome is ever reached.
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4
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0, 11, 11, 1001, 101, 1111, 1001, 10101, 1001, 11011, 1111, 11011, 1111, 11011, 10101, 101101, 10001, 110011, 11011, 1100011, 1100011, 111111, -1, 111111, 11011, 1100011, -1, 11111111, -1, 111111, 101101, 1011101, 100001, 1100011, 110011, -1, 101101, -1, 111111, 1100011, 101101, -1, 111111
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OFFSET
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0,2
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COMMENTS
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The analog of A061563 in base 2. Differs from A062128 only for those n, which are palindromes in base 2.
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LINKS
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EXAMPLE
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23: 10111 -> 10111 + 11101 = 110100 -> 110100 + 1011 = 111111, so a(23) = 111111.
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PROG
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(ARIBAS): stop := 500; for k := 0 to 60 do c := 0; m := k; test := true; while test and c < stop do inc(c); m := m + bit_reverse(m); test := m <> bit_reverse(m); end; if c < stop then bit_write(m); else write(-1); end; write(" "); end; .
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CROSSREFS
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KEYWORD
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base,easy,sign
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AUTHOR
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STATUS
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approved
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