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 A038340 Second line of 5-wave sequence A038201. 0
 1, 4, 9, 50, 105, 616, 1287, 7601, 15873, 93819, 195910, 1158052, 2418195, 14294449, 29849041, 176444054, 368442700, 2177943781, 4547886208, 26883530748, 56137003923, 331837870408, 692929213991, 4096053203771, 8553197751125 (list; graph; refs; listen; history; text; internal format)
 OFFSET 0,2 LINKS F. v. Lamoen, Wave sequences Index entries for linear recurrences with constant coefficients, signature (0,15,0,-35,0,28,0,-9,0,1). FORMULA G.f.: (x^7+x^6-6*x^5-5*x^4+10*x^3+6*x^2-4*x-1) / (x^10-9*x^8+28*x^6-35*x^4+15*x^2-1). - Alois P. Heinz, Jul 16 2009 MAPLE a:= n-> (Matrix([`if`(irem(n, 2)=0, [9, 1, 0, -1, -4], [4, 0, -1, -3, -9])]). Matrix(5, (i, j)-> if i=j-1 then 1 elif j=1 then [15, -35, 28, -9, 1][i] else 0 fi)^iquo(n+1, 2))[1, 2]: seq(a(n), n=0..24); # Alois P. Heinz, Jul 16 2009 CROSSREFS Sequence in context: A053925 A053943 A053955 * A016489 A030694 A060998 Adjacent sequences:  A038337 A038338 A038339 * A038341 A038342 A038343 KEYWORD nonn,easy AUTHOR STATUS approved

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