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Search: id:A114476
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| A114476 |
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Triangle read by rows: inverse of triangle in A061554 with signs in each column +,+,-,-,+,+,-,-,... |
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+0
1
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| 1, -1, 1, 3, -1, 1, -3, 4, -1, 1, 5, -4, 5, -1, 1, -5, 9, -5, 6, -1, 1, 7, -9, 14, -6, 7, -1, 1, -7, 16, -14, 20, -7, 8, -1, 1, 9, -16, 30, -20, 27, -8, 9, -1, 1, -9, 25, -30, 50, -27, 35, -9, 10, -1, 1, 11, -25, 55, -50, 77, -35, 44, -10, 11, -1, 1, -11, 36, -55, 105, -77, 112, -44, 54, -11, 12, -1, 1, 13, -36, 91, -105, 182, -112, 156
(list; table; graph; listen)
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OFFSET
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0,4
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COMMENT
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Unsigned row sums appear to be A014739.
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EXAMPLE
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Start with a signed version of A061554:
1;
1, 1;
-2, 1, 1;
-3, -3, 1, 1;
6, -4, -4, 1, 1;
10, 10, -5, -5, 1;
...
and invert it, getting:
1
-1, 1;
3, -1, 1;
-3, 4, -1, 1;
5, -4, 5, -1, 1;
-5, 9, -5, 6, -1, 1;
...
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MAPLE
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A061554 := proc(n, k) binomial(n+k, floor(k/2)) ; end: nmax := 13 : A := array(1..nmax, 1..nmax) : for r from 1 to nmax do for c from 1 to nmax do A[r, c] := A061554(c-1, r-c)*(-1)^floor((r-c)/2) ; od: od: A := linalg[inverse](A) : for r from 1 to nmax do for c from 1 to r do printf("%d, ", A[r, c]) ; od: od: - R. J. Mathar (mathar(AT)strw.leidenuniv.nl), Jan 31 2008
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CROSSREFS
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Sequence in context: A133116 A059959 A051120 this_sequence A117184 A035690 A124794
Adjacent sequences: A114473 A114474 A114475 this_sequence A114477 A114478 A114479
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KEYWORD
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sign,tabl,easy
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AUTHOR
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Gary Adamson, Nov 27 2006
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EXTENSIONS
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Edited by N. J. A. Sloane (njas(AT)research.att.com), Dec 01 2006
More terms from R. J. Mathar (mathar(AT)strw.leidenuniv.nl), Jan 31 2008
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