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 OFFSET 0,2 LINKS Vincenzo Librandi, Table of n, a(n) for n = 0..5000 Index entries for linear recurrences with constant coefficients, signature (0,3,0,-2). FORMULA a(0)=1; for n > 0, a(n) = a(n-1)*(1 + n mod 2) + 2*((n+1) mod 2). G.f.: (2*x^3 + x^2 + 2*x + 1)/(2*x^4 - 3*x^2 + 1) 3*2^ceiling(n/2) + (-1)^n - 3. - Ralf Stephan, Dec 04 2004 a(2*n) = A033484(n). a(n-1) + a(n) = A061776(n) for n > 0. MATHEMATICA LinearRecurrence[{0, 3, 0, -2}, {1, 2, 4, 8}, 50] (* Harvey P. Dale, May 03 2016 *) PROG (PARI) print1(a=1, ", "); for(n=1, 20, print1(a=2*a, ", ", a=a+2, ", ")) (MAGMA) [3*2^Ceiling(n/2) + (-1)^n - 3: n in [0..50]]; // Vincenzo Librandi, Aug 17 2011 CROSSREFS Cf. A033484, A061776, A075427, A083416. Sequence in context: A173816 A287266 A185400 * A033092 A177909 A259386 Adjacent sequences:  A099939 A099940 A099941 * A099943 A099944 A099945 KEYWORD nonn,easy AUTHOR N. J. A. Sloane, Nov 12 2004 EXTENSIONS Edited and extended by Klaus Brockhaus, Nov 13 2004 STATUS approved

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