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Search: id:A081539
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| A081539 |
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Triangle read by rows in which the n-th row contains the n numbers in increasing order formed by the concatenation of first n-1 numbers. (The digits of the numbers with 2 or more digits are taken as one entity.) First row is taken to be 0. |
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4
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| 0, 1, 2, 12, 13, 23, 123, 124, 134, 234, 1234, 1235, 1245, 1345, 2345, 12345, 12346, 12356, 12456, 13456, 23456, 123456, 123457, 123467, 123567, 124567, 134567, 234567, 1234567, 1234568, 1234578, 1234678, 1235678, 1245678, 1345678, 2345678
(list; table; graph; listen)
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OFFSET
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1,3
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EXAMPLE
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0; 1,2; 12,13,23; 123,124,134,234; 1234,1235,1245,1345,2345; 12345,12346, ...
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MAPLE
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conca := proc(S) local resul, d, i ; resul := 0 ; for i from 1 to nops(S) do d := ilog10(op(i, S))+1 ; resul := resul*10^d+op(i, S) ; od ; resul ; end: A081539 := proc(row) local a, p, i; if row =1 then RETURN([0]) ; fi ; a := [] ; p := [seq(i, i=1..row)] ; for i from 1 to row do a := [op(a), conca(subsop(i=NULL, p))] ; od: sort(a)[1..row] ; end: for n from 1 to 10 do op(A081539(n)) ; od ; - R. J. Mathar (mathar(AT)strw.leidenuniv.nl), Jul 15 2007
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CROSSREFS
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Cf. A081540.
Sequence in context: A143795 A032931 A072483 this_sequence A141273 A010097 A103761
Adjacent sequences: A081536 A081537 A081538 this_sequence A081540 A081541 A081542
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KEYWORD
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nonn,tabl
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AUTHOR
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Amarnath Murthy (amarnath_murthy(AT)yahoo.com), Mar 29 2003
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EXTENSIONS
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More terms from R. J. Mathar (mathar(AT)strw.leidenuniv.nl), Jul 15 2007
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