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A070878
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Stern's diatomic array read by rows (version 2).
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6
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1, 0, 1, 1, 0, 1, 2, 1, 1, 0, 1, 3, 2, 3, 1, 2, 1, 1, 0, 1, 4, 3, 5, 2, 5, 3, 4, 1, 3, 2, 3, 1, 2, 1, 1, 0, 1, 5, 4, 7, 3, 8, 5, 7, 2, 7, 5, 8, 3, 7, 4, 5, 1, 4, 3, 5, 2, 5, 3, 4, 1, 3, 2, 3, 1, 2, 1, 1, 0, 1, 6, 5, 9, 4, 11, 7, 10, 3, 11, 8, 13, 5, 12, 7, 9, 2, 9, 7, 12, 5, 13, 8, 11, 3, 10, 7, 11, 4, 9, 5
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OFFSET
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0,7
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COMMENTS
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Row n has length 2^n + 1.
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LINKS
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FORMULA
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Each row is obtained by copying the previous row but interpolating the sums of pairs of adjacent terms. E.g. after 1 2 1 1 0 we get 1 1+2 2 2+1 1 1+1 1 1+0 0.
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EXAMPLE
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Triangle begins:
1,0;
1,1,0;
1,2,1,1,0;
1,3,2,3,1,2,1,1,0;
...
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MATHEMATICA
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row[1] = {1, 0}; row[n_] := row[n] = (r = row[n-1]; Riffle[r, Most[r + RotateLeft[r]]]); Flatten[ Table[row[n], {n, 1, 7}]] (* Jean-François Alcover, Nov 03 2011 *)
Flatten[NestList[Riffle[#, Total/@Partition[#, 2, 1]]&, {1, 0}, 6]] (* Harvey P. Dale, Dec 06 2014 *)
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CROSSREFS
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Rows sums are A007051. See A293160 for number of distinct terms in each row.
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KEYWORD
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nonn,tabf,nice,easy
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AUTHOR
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EXTENSIONS
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More terms from Antonio G. Astudillo (afg_astudillo(AT)lycos.com), Apr 07 2003
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STATUS
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approved
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