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 A253092 Log_3(A133579(n)). 2
 0, 0, 1, 0, 1, 2, 1, 2, 3, 1, 2, 3, 2, 3, 4, 3, 4, 5, 3, 4, 5, 4, 5, 6, 5, 6, 7, 4, 5, 6, 5, 6, 7, 6, 7, 8, 6, 7, 8, 7, 8, 9, 8, 9, 10, 8, 9, 10, 9, 10, 11, 10, 11, 12, 9, 10, 11, 10, 11, 12, 11, 12, 13, 11, 12, 13, 12, 13, 14, 13, 14, 15, 13, 14, 15, 14, 15, 16 (list; graph; refs; listen; history; text; internal format)
 OFFSET 0,6 COMMENTS Using the definition of A133579 this amounts to a(n) = a(n-1)-valuation_3(n) if n=3k, and a(n) = a(n-1)+1 else. - M. F. Hasler, Feb 15 2015 LINKS M. F. Hasler, Table of n, a(n) for n = 0..3000 EXAMPLE a(18)=a(17)-2 because 18=3^2, a(81)=a(80)-4 because 81=3^4. MATHEMATICA nxt[{n_, a_}] := {n + 1, If[CoprimeQ[a, n + 1], 3 a, a/GCD[a, n + 1]]}; Log[3, #]&/@Join[{1}, Transpose[NestList[nxt, {1, 1}, 80]][[2]]] (* Harvey P. Dale, Feb 14 2015 *) PROG (PARI) a=-1; A253092=vector(1000, n, a+=if(n%3, 1, -valuation(n, 3))) \\ M. F. Hasler, Feb 15 2015 CROSSREFS Cf. A133579. Sequence in context: A057945 A285730 A280055 * A194546 A115452 A039676 Adjacent sequences:  A253089 A253090 A253091 * A253093 A253094 A253095 KEYWORD nonn AUTHOR N. J. A. Sloane, Feb 14 2015 STATUS approved

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Last modified May 7 02:20 EDT 2021. Contains 343636 sequences. (Running on oeis4.)