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 A187179 Number of nontrivial compositions of differential operations and directional derivative of the n-th order on the space R^10. 0
 7, 7, 8, 9, 11, 14, 19, 27, 40, 61, 95, 150, 239, 383, 616, 993, 1603, 2590, 4187, 6771, 10952, 17717, 28663, 46374, 75031, 121399, 196424, 317817, 514235, 832046, 1346275, 2178315, 3524584, 5702893, 9227471, 14930358, 24157823 (list; graph; refs; listen; history; text; internal format)
 OFFSET 1,1 LINKS Ivana Jovović and Branko Malešević, Some enumerations of non-trivial composition of the differential operations and the directional derivative, Notes on Number Theory and Discrete Mathematics, Vol. 23, 2017, No. 1, 28-38. Index entries for linear recurrences with constant coefficients, signature (2,0,-1). FORMULA a(n) = A000045(n) + 6. a(n) = 2*a(n-1)-a(n-3). G.f.: -x*(6*x^2+7*x-7) / ((x-1)*(x^2+x-1)). [Colin Barker, Dec 14 2012] MATHEMATICA LinearRecurrence[{2, 0, -1}, {7, 7, 8}, 40] (* Harvey P. Dale, Apr 29 2015 *) CROSSREFS Cf. A000045. Sequence in context: A024818 A076236 A072520 * A110941 A182470 A157290 Adjacent sequences:  A187176 A187177 A187178 * A187180 A187181 A187182 KEYWORD nonn,easy AUTHOR Branko Malesevic, Mar 06 2011 STATUS approved

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Last modified September 19 14:36 EDT 2020. Contains 337178 sequences. (Running on oeis4.)