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A001779
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Expansion of 1/((1+x)(1-x)^8).
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3
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1, 7, 29, 91, 239, 553, 1163, 2269, 4166, 7274, 12174, 19650, 30738, 46782, 69498, 101046, 144111, 201993, 278707, 379093, 508937, 675103, 885677, 1150123, 1479452, 1886404, 2385644, 2993972
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OFFSET
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0,2
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COMMENTS
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a(n) is the number of positive terms in the expansion of (a_1+a_2+a_3+a_4+a_5+a_6+a_7-z)^n. Also the convolution of A001769 and A000012; A001753 and A001477; A001752 and A000217; A002623 and A000292; A002620 and A000332; A004526 and A000389. - Sergio Falcon (sfalcon(AT)dma.ulpgc.es), Feb 13 2007
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LINKS
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Vincenzo Librandi, Table of n, a(n) for n = 0..10000
Index to sequences with linear recurrences with constant coefficients, signature (7,-20,28,-14,-14,28,-20,7,-1).
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FORMULA
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a(n)=(-1)^{7-n} sum_{i=0}^n ((-1)^{7-i} binomial{7+i,i}) - Sergio Falcon (sfalcon(AT)dma.ulpgc.es), Feb 13 2007
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MAPLE
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A001779 := proc(n) 1/80640*(2*n+9) *(4*n^6 +108*n^5 +1138*n^4 +5904*n^3 +15628*n^2 +19638*n +8925)+(-1)^n/256 ; end proc:
seq(A001779(n), n=0..50) ; # R. J. Mathar, Mar 22 2011
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PROG
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(MAGMA) [1/80640*(2*n+9) *(4*n^6 +108*n^5 +1138*n^4 +5904*n^3 +15628*n^2 +19638*n +8925)+(-1)^n/256 : n in [0..30]]; // Vincenzo Librandi, =ct 08 2011
(PARI) a(n)=(2*n+9)*(4*n^6+108*n^5+1138*n^4+5904*n^3+15628*n^2+19638*n) \/ 80640+1 \\ Charles R Greathouse IV, Apr 17 2012
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CROSSREFS
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Sequence in context: A079796 A114043 A166189 * A053295 A055798 A002664
Adjacent sequences: A001776 A001777 A001778 * A001780 A001781 A001782
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KEYWORD
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nonn,easy
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AUTHOR
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N. J. A. Sloane.
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STATUS
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approved
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