A229205 - OEIS

%I #26 Mar 14 2015 01:03:13

%S 1,3,10,13,19,22,30,33,38,47,53,59,69,71,78,82,87,97,107,110,115,129,

%T 138,146,151,158,161,167,173,182,187,197,210,218,223,227,233,249,255,

%U 265,267,278,285,295,299,305,314,318,327,334,346,357,367

%N Lucky numbers generated from squarefree numbers.

%C Follow same procedure that is used to produce the lucky numbers A000959 but start with squarefree numbers A005117 instead of natural numbers.

%e Start with squarefree numbers A005117 = (1, 2, 3, 5, 6, 7, 10, 11, 13, 14, 15, 17, 19, 21, 22, 23, 26, 29, 30,...).

%e Delete every second number to get (1,_ 3,_ 6,_ 10,_ 13,_ 15,_ 19,_ 22,_ 26,_ 30, ...).

%e Since the next larger remaining number is 3, delete every 3rd number, to get (1, 3,_ 10, 13,_ 19, 22,_ 30, ...).

%e The next larger remaining number is 10, so delete every 10th term, etc. Note that "30" will remain in this sequence, but is not among the squarefree numbers indexed by lucky numbers, A229483. - _M. F. Hasler_, Sep 24 2013

%o (PARI) list_A229205(Nmax)={my(v=(select(issquarefree,vector(Nmax,i,i))),i,k);while(v[i=k+++(v[k]==1)]<=#v,v=vecextract(v,2^#v-1-sum(j=1,#v\v[i],2^(v[i]*j-1))));v} \\ _M. F. Hasler_, Sep 24 2013

%Y Cf. A059987, A032605, A229483.

%K nonn

%O 1,2

%A _Irina Gerasimova_, Sep 16 2013