cp's OEIS Frontend

A080728 a(0) = 3; for n>0, a(n) is taken to be the smallest positive integer greater than a(n-1) which is consistent with the condition "n is a member of the sequence if and only if a(n) == 2 mod 3".

%I A080728 #12 Mar 30 2012 17:27:40
%S A080728 3,4,6,8,11,12,14,15,17,18,19,20,23,24,26,29,30,32,35,38,41,42,43,44,
%T A080728 47,48,50,51,52,53,56,57,59,60,61,62,63,64,65,66,67,68,71,74,77,78,79,
%U A080728 80,83,84,86,89,92,95,96,97,98,101,102,104,107,110,113,116,119,122,125,128
%N A080728 a(0) = 3; for n>0, a(n) is taken to be the smallest positive integer greater than a(n-1) which is consistent with the condition "n is a member of the sequence if and only if a(n) == 2 mod 3".
%H A080728 B. Cloitre, N. J. A. Sloane and M. J. Vandermast, <a href="http://www.cs.uwaterloo.ca/journals/JIS/VOL6/Cloitre/cloitre2.html">Numerical analogues of Aronson's sequence</a>, J. Integer Seqs., Vol. 6 (2003), #03.2.2.
%H A080728 B. Cloitre, N. J. A. Sloane and M. J. Vandermast, <a href="http://arXiv.org/abs/math.NT/0305308">Numerical analogues of Aronson's sequence</a> (math.NT/0305308)
%H A080728 <a href="/index/Aa#aan">Index entries for sequences of the a(a(n)) = 2n family</a>
%F A080728 a(a(n)) = 3*n+8, n >= 0.
%o A080728 (PARI) {a=3; m=[3]; for(n=1,68,print1(a,","); a=a+1; if(a%3==2&&a==n,qwqw=qwqw,if(m==[], while((a%3!=2&&a==n)||a%3==2,a++),if(m[1]==n, while(a%3!=2,a++); m=if(length(m)==1,[],vecextract(m,"2..")),if(a%3==2,a++))); m=concat(m,a)))}
%Y A080728 Cf. A079000, A080720, ...
%K A080728 nonn,easy
%O A080728 0,1
%A A080728 _N. J. A. Sloane_, Mar 08 2003
%E A080728 More terms and PARI code from _Klaus Brockhaus_, Mar 09 2003