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A031087
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Triangle T(n,k): write n in base 9, reverse order of digits.
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22
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0, 1, 2, 3, 4, 5, 6, 7, 8, 0, 1, 1, 1, 2, 1, 3, 1, 4, 1, 5, 1, 6, 1, 7, 1, 8, 1, 0, 2, 1, 2, 2, 2, 3, 2, 4, 2, 5, 2, 6, 2, 7, 2, 8, 2, 0, 3, 1, 3, 2, 3, 3, 3, 4, 3, 5, 3, 6, 3, 7, 3, 8, 3, 0, 4, 1, 4, 2, 4, 3, 4, 4, 4, 5, 4, 6, 4, 7, 4, 8, 4, 0, 5, 1, 5, 2, 5, 3, 5, 4, 5
(list;
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listen;
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internal format)
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OFFSET
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0,3
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LINKS
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PROG
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(PARI) A031087(n, k=-1)=/*k<0&&error("Flattened sequence not yet implemented.")*/n\9^k%9 \\ Assuming that columns are numbered starting with k=0 as in A030308, A030567 and others. - M. F. Hasler, Jul 21 2013
(Haskell)
a031087 n k = a031087_row n !! (k-1)
a031087_row n | n < 9 = [n]
| otherwise = m : a031087_row n' where (n', m) = divMod n 9
a031087_tabf = map a031087_row [0..]
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CROSSREFS
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KEYWORD
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nonn,base,tabf,less
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AUTHOR
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EXTENSIONS
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STATUS
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approved
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