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A129765
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Triangle, (1, 1, 2, 2, 2, ...) in every column.
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2
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1, 1, 1, 2, 1, 1, 2, 2, 1, 1, 2, 2, 2, 1, 1, 2, 2, 2, 2, 1, 1, 2, 2, 2, 2, 2, 1, 1, 2, 2, 2, 2, 2, 2, 1, 1, 2, 2, 2, 2, 2, 2, 2, 1, 1, 2, 2, 2, 2, 2, 2, 2, 2, 1, 1, 2, 2, 2, 2, 2, 2, 2, 2, 2, 1, 1, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 1, 1, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 1, 1, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 1, 1
(list;
table;
graph;
refs;
listen;
history;
text;
internal format)
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OFFSET
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1,4
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COMMENTS
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Row sums = A004277, (1, 2, 4, 6, 8, 10, ...). Binomial transform of (1, 1, 2, 2, 2, ...) = A000325, starting (1, 2, 5, 12, 27, 58, ...). Binomial transform of A130196 = A130197, a triangle with row sums = the Cullen numbers, A002064.
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LINKS
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FORMULA
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Triangle, (1, 1, 2, 2, 2, ...) in every column. By rows, (1; 1, 1; 2, 1, 1; ...), continuing with (n-2) 2's followed by two 1's. Inverse of A000012 as an infinite lower triangular matrix (all 1's and the rest zeros), signed by columns: (+ - - + + - -, ...).
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EXAMPLE
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First few rows of the triangle:
1;
1, 1;
2, 1, 1;
2, 2, 1, 1;
2, 2, 2, 1, 1;
...
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MAPLE
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A129765 := proc(n, m) if abs(n-m)<2 then 1 ; else 2 ; end if ; end proc:
for n from 1 to 18 do for m from 1 to n do printf("%d, ", A129765(n, m)) ; od ; od ; # R. J. Mathar, Jun 08 2007
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MATHEMATICA
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Table[PadLeft[{1, 1}, n, 2], {n, 20}]//Flatten (* Harvey P. Dale, May 20 2019 *)
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CROSSREFS
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KEYWORD
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AUTHOR
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EXTENSIONS
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STATUS
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approved
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