Search: id:A077985
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%I A077985
%S A077985 1,2,5,12,29,70,169,408,985,2378,5741,13860,33461,80782,195025,470832,
               1136689,
%T A077985 2744210,6625109,15994428,38613965,93222358,225058681,543339720,1311738121,
%U A077985 3166815962,7645370045,18457556052,44560482149,107578520350,259717522849
%V A077985 1,-2,5,-12,29,-70,169,-408,985,-2378,5741,-13860,33461,-80782,195025,
               -470832,1136689,
%W A077985 -2744210,6625109,-15994428,38613965,-93222358,225058681,-543339720,1311738121,
%X A077985 -3166815962,7645370045,-18457556052,44560482149,-107578520350,259717522849
%N A077985 Expansion of 1/(1+2*x-x^2).
%H A077985 <a href="Sindx_Rea.html#recLCC">Index entries for sequences related to 
               linear recurrences with constant coefficients</a>
%H A077985 Tanya Khovanova, <a href="http://www.tanyakhovanova.com/RecursiveSequences/
               RecursiveSequences.html">Recursive Sequences</a>
%F A077985 a(n) = (-1)^n * A000129(n+1) [From M. F. Hasler (Maximilian.Hasler(AT)gmail.com), 
               Oct 05 2008]
%F A077985 a(0)=1, a(1)=-2, a(n)=-2*a(n-1)+a(n-2) for n>1 . [From Philippe DELEHAM 
               (kolotoko(AT)wanadoo.fr), Sep 19 2009]
%e A077985 sage: taylor( mul(x/(1 + 2*x - x^2) for i in xrange(1,2)),x,0,31)# solution: 
               x - 2*x^2 + 5*x^3 - 12*x^4 + 29*x^5 - 70*x^6 + 169*x^7 - 408*x^8 
               + 985*x^9 - 2378*x^10 + 5741*x^11 - 13860*x^12 + 33461*x^13 - 80782*x^14 
               + 195025*x^15 - 470832*x^16 + 1136689*x^17 - 2744210*x^18 + 6625109*x^19 
               - 15994428*x^20 + 38613965*x^21 - 93222358*x^22 + 225058681*x^23 
               - 543339720*x^24 + 1311738121*x^25 - 3166815962*x^26 + 7645370045*x^27 
               - 18457556052*x^28 + 44560482149*x^29 - 107578520350*x^30 + 259717522849*x^31 
               [From Zerinvary Lajos (zerinvarylajos(AT)yahoo.com), May 29 2009]
%o A077985 (Other) sage: taylor( mul(x/(1 + 2*x - x^2) for i in xrange(1,2)),x,0,
               31)# [From Zerinvary Lajos (zerinvarylajos(AT)yahoo.com), May 29 
               2009]
%Y A077985 Essentially the same as A000129, which is the main entry for these numbers.
%Y A077985 Sequence in context: A048624 A000129 A141682 this_sequence A054198 A054196 
               A131710
%Y A077985 Adjacent sequences: A077982 A077983 A077984 this_sequence A077986 A077987 
               A077988
%K A077985 sign
%O A077985 0,2
%A A077985 N. J. A. Sloane (njas(AT)research.att.com), Nov 17 2002

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