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The largest positive even integer that can be represented with n digits in base 3/2.
3

%I #34 Sep 21 2022 01:42:16

%S 2,4,8,14,22,34,52,80,122,184,278,418,628,944,1418,2128,3194,4792,

%T 7190,10786,16180,24272,36410,54616,81926,122890,184336,276506,414760,

%U 622142,933214,1399822,2099734,3149602,4724404,7086608,10629914,15944872,23917310

%N The largest positive even integer that can be represented with n digits in base 3/2.

%H Michael De Vlieger, <a href="/A305497/b305497.txt">Table of n, a(n) for n = 1..1000</a>

%H B. Chen, R. Chen, J. Guo, S. Lee et al., <a href="http://arxiv.org/abs/1808.04304">On Base 3/2 and its Sequences</a>, arXiv:1808.04304 [math.NT], 2018.

%F a(n+1) = 2*floor(3*a(n)/4) + 2.

%F a(n) = 2*A061419(n+1) - 2.

%F a(n) = A305498(n+1) - 2.

%F a(n) = Sum_{i=0..n-1} (3/2)^i*A304274(n-i). - _Alois P. Heinz_, Jun 21 2018

%t b[n_] := b[n] = If[n == 1, 2, Function[t, t + Mod[t, 2]][3/2 b[n - 1]]]; a[n_] := b[n + 1] - 3/2 b[n] + 1; A305497[n_] := Sum[(3/2)^i*a[n - i], {i, 0, n - 1}]; Table[A305497[n], {n, 1, 39}] (* _Robert P. P. McKone_, Feb 12 2021 *)

%o (Python)

%o from itertools import islice

%o def A305497_gen(): # generator of terms

%o a = 2

%o while True:

%o a += a>>1

%o yield (a<<1)-4

%o A305497_list = list(islice(A305497_gen(),70)) # _Chai Wah Wu_, Sep 20 2022

%Y Cf. A005428, A070885, A073941, A081848, A024629, A246435, A304023, A304024, A304025, A303500, A304272, A304273, A304274, A305498.

%K nonn,base

%O 1,1

%A _Tanya Khovanova_ and PRIMES STEP Senior group, Jun 02 2018