%I #23 Jan 01 2024 23:49:56
%S 1,3,5,2,4,6,7,9,11,8,10,12,13,15,17,14,16,18,19,21,23,20,22,24,25,27,
%T 29,26,28,30,31,33,35,32,34,36,37,39,41,38,40,42,43,45,47,44,46,48,49,
%U 51,53,50,52,54,55,57,59,56,58,60,61,63,65,62,64,66,67,69,71,68,70,72
%N 3 odds, 3 evens.
%H Robert Israel, <a href="/A131793/b131793.txt">Table of n, a(n) for n = 1..10000</a>
%H <a href="/index/Rec#order_07">Index entries for linear recurrences with constant coefficients</a>, signature (1,0,0,0,0,1,-1).
%H <a href="/index/Per#IntegerPermutation">Index entries for sequences that are permutations of the natural numbers</a>.
%F a(n) = 2*(3*floor((n-1)/6)+((n-1) mod 3)+1)-(floor((n+2)/3) mod 2). - _Joshua Zucker_, Aug 29 2012
%F G.f.: x*(1 + 2*x + 2*x^2 - 3*x^3 + 2*x^4 + 2*x^5)/(1 - x - x^6 + x^7). - _Robert Israel_, May 10 2020
%F Sum_{n>=1} (-1)^(n+1)/a(n) = log(2)/3 + log(3)/2 - Pi/(6*sqrt(3)). - _Amiram Eldar_, Feb 09 2023
%p f:= gfun:-rectoproc({a(n) = a(n-1)+a(n-6)-a(n-7), a(1)=1,a(2)=3,a(3)=5,a(4)=2,a(5)=4,a(6)=6,a(7)=7},a(n),remember):
%p map(f, [$1..100]); # _Robert Israel_, May 10 2020
%t LinearRecurrence[{1, 0, 0, 0, 0, 1, -1}, {1, 3, 5, 2, 4, 6, 7}, 100] (* _Amiram Eldar_, Feb 09 2023 *)
%Y Cf. A271833.
%K nonn
%O 1,2
%A _Paul Curtz_, Oct 23 2007