cp's OEIS Frontend

A276786 a(1) = 1; subsequent terms are defined by the rule that if m is present so are 2m+1 and 3m+1; repeated terms are included; final list is sorted.

%I A276786 #31 Oct 20 2019 21:59:39
%S A276786 1,3,4,7,9,10,13,15,19,21,22,27,28,31,31,39,40,43,45,46,55,57,58,63,
%T A276786 63,64,67,79,81,82,85,87,91,93,94,94,111,115,117,118,121,127,127,129,
%U A276786 130,135,136,139,159,163,165,166,171,172,175,175,183,187,189,189,190,190,193,202,223,231,235,237,238
%N A276786 a(1) = 1; subsequent terms are defined by the rule that if m is present so are 2m+1 and 3m+1; repeated terms are included; final list is sorted.
%C A276786 31 is the first number to appear twice. This is a multi-set version of the Klarner-Rado sequence A002977.
%C A276786 20479 is the first number to appear three times. - _Rémy Sigrist_, Dec 19 2016
%H A276786 Rémy Sigrist, <a href="/A276786/b276786.txt">Table of n, a(n) for n = 1..29993</a> [Terms up to 500000]
%H A276786 J. C. Lagarias, <a href="http://www.jstor.org/stable/10.4169/amer.math.monthly.123.8.753">Erdős, Klarner and the 3x + 1 Problem</a>, Amer. Math. Monthly 123 (No. 8, 2016), 753-776. See S# on page 756.
%H A276786 Rémy Sigrist, <a href="/A276786/a276786.c++.txt">C99 program for A276786</a>
%p A276786 KR:=proc(lis) local i,j,t1,t2,t3;
%p A276786 t1:=lis; t2:=nops(lis); t3:=[];
%p A276786 for i from 1 to t2 do j:=t1[i];
%p A276786 t3:=[op(t3),2*j+1,3*j+1]; od: sort(t3); end;
%p A276786 t:=[1]; b:=[1];
%p A276786 for n from 1 to 10 do
%p A276786 t:=KR(t); b:=[op(b),op(t)]; b:=sort(b);
%p A276786 od: b;
%Y A276786 Cf. A002977. See A276787 for repeated terms.
%K A276786 nonn
%O A276786 1,2
%A A276786 _N. J. A. Sloane_, Oct 06 2016