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 A097950 G.f.: (1+x^5+x^10)/((1-x)*(1-x^3)). 0
 1, 1, 1, 2, 2, 3, 4, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27, 28, 29, 30, 31, 32, 33, 34, 35, 36, 37, 38, 39, 40, 41, 42, 43, 44, 45, 46, 47, 48, 49, 50, 51, 52, 53, 54, 55, 56, 57, 58, 59, 60, 61, 62, 63, 64, 65, 66, 67, 68, 69, 70, 71, 72 (list; graph; refs; listen; history; text; internal format)
 OFFSET 0,4 LINKS G. Nebe, E. M. Rains and N. J. A. Sloane, Self-Dual Codes and Invariant Theory, Springer, Berlin, 2006. E. M. Rains and N. J. A. Sloane, Self-dual codes, pp. 177-294 of Handbook of Coding Theory, Elsevier, 1998 (Abstract, pdf, ps). Index entries for linear recurrences with constant coefficients, signature (2,-1). FORMULA Molien series is (1+x^10+x^20)/((1-x^2)*(1-x^6)). a(n) = n - 3 for n > 7. [Charles R Greathouse IV, Oct 27 2011] MATHEMATICA CoefficientList[Series[(1+x^5+x^10)/((1-x)*(1-x^3)), {x, 0, 80}], x] (* or *) LinearRecurrence[{2, -1}, {1, 1, 1, 2, 2, 3, 4, 4, 5}, 80] (* Harvey P. Dale, Oct 11 2015 *) PROG (PARI) a(n)=if(n>7, n-3, [1, 1, 1, 2, 2, 3, 4, 4][n+1]) \\ Charles R Greathouse IV, Oct 27 2011 CROSSREFS Sequence in context: A241948 A051068 A050294 * A011885 A211524 A008672 Adjacent sequences:  A097947 A097948 A097949 * A097951 A097952 A097953 KEYWORD nonn,easy AUTHOR N. J. A. Sloane, Sep 06 2004 STATUS approved

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Last modified July 24 21:47 EDT 2021. Contains 346273 sequences. (Running on oeis4.)