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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; internal format)
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OFFSET
| 1,4
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COMMENTS
| 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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FORMULA
| 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
| First few rows of the triangle are:
1;
1, 1;
2, 1, 1;
2, 2, 1, 1;
2, 2, 2, 1, 1;
...
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MAPLE
| A129765 := proc(n, m) if abs(n-m)<2 then 1 ; else 2 ; fi ; end: for n from 1 to 18 do for m from 1 to n do printf("%d, ", A129765(n, m)) ; od ; od ; - R. J. Mathar (mathar(AT)strw.leidenuniv.nl), Jun 08 2007
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CROSSREFS
| Cf. A004277, A002064, A000325, A130197.
Sequence in context: A174886 A157415 A154325 * A143187 A143209 A163994
Adjacent sequences: A129762 A129763 A129764 * A129766 A129767 A129768
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KEYWORD
| nonn,tabl,easy
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AUTHOR
| Gary W. Adamson (qntmpkt(AT)yahoo.com), May 16 2007
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EXTENSIONS
| More terms from R. J. Mathar (mathar(AT)strw.leidenuniv.nl), Jun 08 2007
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