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 A007893 A Kutz sequence. 1
 1, 4, 9, 16, 1, 4, 9, 16, 25, 4, 9, 16, 25, 36, 9, 16, 25, 36, 49, 16, 25, 36, 49, 64, 25, 36, 49, 64, 81, 36, 49, 64, 81, 100, 49, 64, 81, 100, 121, 64, 81, 100, 121, 144, 81, 100, 121, 144, 169, 100, 121, 144, 169, 196, 121, 144, 169, 196, 225, 144, 169, 196 (list; graph; refs; listen; history; text; internal format)
 OFFSET 1,2 LINKS Vincenzo Librandi, Table of n, a(n) for n = 1..10000 R. E. Kutz, Two unusual sequences, Two-Year College Mathematics Journal, 12 (1981), 316-319. Index entries for linear recurrences with constant coefficients, signature (1,0,0,0,2,-2,0,0,0,-1,1). FORMULA The pattern is obvious! a(n) = (n - 4*floor(n/5))^2. - Michael Somos, Jun 01 1999 G.f.: x*(1+3*x+5*x^2+7*x^3-15*x^4+x^5-x^6-3*x^7-5*x^8+9*x^9) / ((1-x)^3*(1+x+x^2+x^3+x^4)^2). - Colin Barker, Aug 05 2016 MATHEMATICA Table[(n - 4*Floor[n/5])^2, {n, 60}] (* Arkadiusz Wesolowski, Sep 29 2011 *) LinearRecurrence[{1, 0, 0, 0, 2, -2, 0, 0, 0, -1, 1}, {1, 4, 9, 16, 1, 4, 9, 16, 25, 4, 9}, 80] (* or *) Join[ Range[4]^2, Flatten[Partition[Range[20]^2, 5, 1]]] (* Harvey P. Dale, May 11 2022 *) PROG (MAGMA) [(n-4*Floor(n/5))^2: n in [1..60]]; // Vincenzo Librandi, Sep 30 2011 (PARI) Vec(x*(1+3*x+5*x^2+7*x^3-15*x^4+x^5-x^6-3*x^7-5*x^8+9*x^9)/((1-x)^3*(1+x+x^2+x^3+x^4)^2) + O(x^60)) \\ Colin Barker, Aug 05 2016 CROSSREFS Sequence in context: A106548 A106546 A276191 * A070446 A258682 A070445 Adjacent sequences:  A007890 A007891 A007892 * A007894 A007895 A007896 KEYWORD nonn,easy AUTHOR STATUS approved

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Last modified July 2 13:44 EDT 2022. Contains 355007 sequences. (Running on oeis4.)