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A077882
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Expansion of x/((1-x)*(1-x^2-2*x^3)).
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0
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0, 1, 1, 2, 4, 5, 9, 14, 20, 33, 49, 74, 116, 173, 265, 406, 612, 937, 1425, 2162, 3300, 5013, 7625, 11614, 17652, 26865, 40881, 62170, 94612, 143933, 218953, 333158, 506820, 771065, 1173137, 1784706, 2715268, 4130981, 6284681, 9561518, 14546644, 22130881, 33669681
(list; graph; refs; listen; history; internal format)
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OFFSET
| 0,4
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COMMENTS
| a(n+1) gives diagonal sums of Riordan array (1/(1-x),x(1+2x)) and partial sums of A052947. - Paul Barry (pbarry(AT)wit.ie), Jul 18 2005
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FORMULA
| a(n) = a(n-1)+a(n-2)+a(n-3)-2*a(n-4) - Roger Bagula (rlbagulatftn(AT)yahoo.com), Mar 25 2005
a(n+1)=sum{k=0..n, sum{j=0..floor(k/2), C(j, k-2j)2^(k-2j)}}; - Paul Barry (pbarry(AT)wit.ie), Jul 18 2005
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MATHEMATICA
| {{0, 1, 0, 0}, {0, 0, 1, 0}, {0, 0, 0, 1}, {-2, 1, 1, 1}}.{a[n - 4], a[n - 3], a[n - 2], a[n - 1]} a[0] = 0; a[1] = 1; a[2] = 1; a[3] = 2; a[n_Integer?Positive] := a[n] = a[n - 1] + a[n - 2] + a[n - 3] - 2a[n - 4]; aa = Table[a[n], {n, 0, 200}] - Roger Bagula (rlbagulatftn(AT)yahoo.com), Mar 25 2005
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CROSSREFS
| Sequence in context: A129282 A073153 A073154 * A120939 A120770 A073151
Adjacent sequences: A077879 A077880 A077881 * A077883 A077884 A077885
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KEYWORD
| nonn
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AUTHOR
| N. J. A. Sloane (njas(AT)research.att.com), Nov 17 2002
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EXTENSIONS
| Edited by N. J. A. Sloane (njas(AT)research.att.com), Aug 29 2008 at the suggestion of R. J. Mathar
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