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 A328262 a(n) = a(n-1)*3/2, if noninteger then rounded to the nearest even integer, with a(1) = 1. 1
 1, 2, 3, 4, 6, 9, 14, 21, 32, 48, 72, 108, 162, 243, 364, 546, 819, 1228, 1842, 2763, 4144, 6216, 9324, 13986, 20979, 31468, 47202, 70803, 106204, 159306, 238959, 358438, 537657, 806486, 1209729, 1814594, 2721891, 4082836, 6124254, 9186381, 13779572, 20669358, 31004037 (list; graph; refs; listen; history; text; internal format)
 OFFSET 1,2 COMMENTS On average, about one out of every three numbers will have been rounded, since after each rounding there is a 1 in 1 chance of the next number being divisible by 2, 1 in 2 of being divisible by 2^2, and so on, leading to an average of the number after a rounding being divisible by 2^2, requiring three terms (including itself) to reach a point where it needs to round again. There doesn't seem to be any pattern to whether the roundings are up or down, and they seem to each be equally likely. LINKS Robert Israel, Table of n, a(n) for n = 1..5657 MAPLE R:= 1: r:= 1: for i from 1 to 100 do r:= r*3/2; if not r::integer then v:= floor(r); if v::even then r:= v else r:= v+1 fi; fi; R:= R, r; od: R; # Robert Israel, Jan 10 2023 MATHEMATICA f[n_] := If[EvenQ[n], 3n/2, 1 + (3n - Mod[n, 4])/2]; a = 1; a[n_] := a[n] = f[a[n - 1]]; Array[a, 36] (* Amiram Eldar, Oct 12 2019 *) PROG (PARI) seq(n)={my(a=vector(n)); a=1; for(n=2, n, my(t=a[n-1]*3); if(t%2, t+=t%4-2); a[n]=t/2); a} \\ Andrew Howroyd, Oct 11 2019 CROSSREFS Similar to A061418, which always rounds down. Sequence in context: A005428 A355910 A143951 * A292800 A214041 A058355 Adjacent sequences: A328259 A328260 A328261 * A328263 A328264 A328265 KEYWORD nonn AUTHOR Jason Atwood, Oct 09 2019 STATUS approved

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Last modified November 30 03:08 EST 2023. Contains 367452 sequences. (Running on oeis4.)