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 A074308 Inverse of permutation in A074307. 4
 0, 3, 1, 2, 9, 5, 8, 6, 18, 12, 10, 4, 27, 7, 17, 15, 36, 21, 19, 11, 45, 14, 26, 24, 54, 30, 28, 13, 63, 16, 35, 33, 72, 39, 37, 20, 81, 23, 44, 42, 90, 48, 46, 22, 99, 25, 53, 51, 108, 57, 55, 29, 117, 32, 62, 60, 126, 66, 64, 31, 135, 34, 71, 69, 144, 75, 73, 38, 153, 41, 80 (list; graph; refs; listen; history; text; internal format)
 OFFSET 0,2 COMMENTS A permutation of the nonnegative integers. REFERENCES G. Venturini, Iterates of number-theoretic functions with periodic rational coefficients (generalization of the 3x+1 problem), Stud. Appl. Math., 86 (1992), 185-218. LINKS FORMULA a(A074307(n)) = n. - R. J. Mathar, Feb 27 2007 MAPLE A074305 := proc(n) option remember ; local m ; m := floor(n/3) ; if 3*m = n then 2*m ; elif 3*m+1 =n then 4*m+3 ; else 4*m+1 ; fi ; end: A074307 := proc(n) A074305(A074305(n)) ; end: A074308 := proc(n) local a ; a := 0 ; while A074307(a) <> n do a := a+1 ; od ; RETURN(a) ; end: for n from 0 to 70 do printf("%d, ", A074308(n)) ; od ; # R. J. Mathar, Feb 27 2007 CROSSREFS Cf. A074305, A074306, A074307. Sequence in context: A152252 A152229 A238388 * A237186 A058142 A058144 Adjacent sequences:  A074305 A074306 A074307 * A074309 A074310 A074311 KEYWORD nonn,easy AUTHOR N. J. A. Sloane, Sep 23 2002 EXTENSIONS Corrected and extended by R. J. Mathar, Feb 27 2007 STATUS approved

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Last modified January 22 18:41 EST 2019. Contains 319365 sequences. (Running on oeis4.)