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A253607
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First differences of A253580, when the tree is seen as flattened list.
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6
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1, -1, 2, 1, -2, -1, 2, 2, 1, -2, -2, -1, 2, 2, 2, 1, -2, -2, -2, -1, 2, 2, 2, 2, 1, -2, -2, -2, -2, -1, 2, 2, 2, 2, 2, 1, -2, -2, -2, -2, -2, -1, 2, 2, 2, 2, 2, 2, 1, -2, -2, -2, -2, -2, -2, -1, 2, 2, 2, 2, 2, 2, 2, 1, -2, -2, -2, -2, -2, -2, -2, -1, 2, 2
(list;
graph;
refs;
listen;
history;
text;
internal format)
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OFFSET
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0,3
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COMMENTS
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a(n) != 0 and -2 <= a(n) <= +2.
a(n) = 1 iff A253580(n+1) = A253580(n) + 1, marked with X in the table below, where also the erasure of pairs of consecutive terms in A253580 is illustrated;
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LINKS
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EXAMPLE
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. n | A253580(n) | a(n) | erased | reappearing
. ---+------------+------+--------+-------------
. 0 | X 0 | 1 | 0 |
. 1 | X 1 | -1 | 1 |
. 2 | 0 | 2 | | 0
. 3 | X 2 | 1 | 2 |
. 4 | X 3 | -2 | 3 |
. 5 | 1 | -1 | | 1
. 6 | 0 | 2 | | 0
. 7 | 2 | 2 | | 2
. 8 | X 4 | 1 | 4 |
. 9 | X 5 | -2 | 5 |
. 10 | 3 | -2 | | 3
. 11 | 1 | -1 | | 1
. 12 | 0 | 2 | | 0
. 13 | 2 | 2 | | 2
. 14 | 4 | 2 | | 4
. 15 | X 6 | 1 | 6 |
. 16 | X 7 | -2 | 7 |
. 17 | 5 | -2 | | 5
. 18 | 3 | -2 | | 3
. 19 | 1 | -1 | | 1
. 20 | 0 | 2 | | 0
. 21 | 2 | 2 | | 2
. 22 | 4 | 2 | | 4
. 23 | 6 | 2 | | 6
. 24 | X 8 | 1 | 8 |
. 25 | X 9 | -2 | 9 | .
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PROG
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(Haskell)
a253607 n = a253607_list !! n
a253607_list = zipWith (-) (tail a253580_list) a253580_list
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CROSSREFS
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KEYWORD
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sign
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AUTHOR
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STATUS
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approved
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