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 A116551 Permutation of natural numbers generated by 3-rowed array shown below. 1
 0, 3, 1, 6, 4, 2, 9, 7, 5, 12, 10, 8, 15, 13, 11, 18, 16, 14, 21, 19, 17, 24, 22, 20, 27, 25, 23, 30, 28, 26, 33, 31, 29, 36, 34, 32, 39, 37, 35, 42, 40, 38, 45, 43, 41, 48, 46, 44, 51, 49, 47, 54, 52, 50, 57, 55, 53, 60, 58, 56, 63, 61, 59, 66, 64, 62, 69, 67, 65, 72, 70, 68, 75 (list; graph; refs; listen; history; text; internal format)
 OFFSET 1,2 COMMENTS 0 3 6 9 12 15 18 21 24 ... a(n)= 3n 1 4 7 10 13 16 19 22 25 ... a(n)= 3n+1 2 5 8 11 14 17 20 23 26 ... a(n)= 3n+2 REFERENCES M. Cerasoli, F. Eugeni and M. Protasi, Elementi di Matematica Discreta, Bologna 1988. Emanuele Munarini and Norma Zagaglia Salvi, Matematica Discreta, UTET, CittaStudiEdizioni, Milano 1997. LINKS G. C. Greubel, Table of n, a(n) for n = 1..1000 Index entries for linear recurrences with constant coefficients, signature (1,0,1,-1). FORMULA Starting at the term a(3), a(n+3k) = a(n) + 3k, with k>=1. From Chai Wah Wu, Jul 10 2016: (Start) a(n) = a(n-1) + a(n-3) - a(n-4) for n > 7. G.f.: x^2*(2*x^5 - 5*x^3 + 5*x^2 - 2*x + 3)/(x^4 - x^3 - x + 1). (End) MATHEMATICA Rest[CoefficientList[Series[x^2*(2*x^5 - 5*x^3 + 5*x^2 - 2*x + 3)/(x^4 - x^3 - x + 1), {x, 0, 50}], x]] (* or *) Join[{0, 3, 1, 6, 4, 2, 9}, LinearRecurrence[{1, 0, 1, -1}, {7, 5, 12, 10}, 50]] (* G. C. Greubel, Sep 20 2017 *) PROG (PARI) x='x+O('x^50); Vec(x^2*(2*x^5 - 5*x^3 + 5*x^2 - 2*x + 3)/(x^4 - x^3 - x + 1)) \\ G. C. Greubel, Sep 20 2017 CROSSREFS Cf. A115302. Sequence in context: A209165 A121437 A078585 * A213783 A163330 A021320 Adjacent sequences:  A116548 A116549 A116550 * A116552 A116553 A116554 KEYWORD easy,nonn AUTHOR Giovanni Teofilatto, Mar 17 2006 STATUS approved

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Last modified April 22 11:46 EDT 2019. Contains 322330 sequences. (Running on oeis4.)