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Binary expansion of n has form 11**...*1.
3

%I #7 Sep 04 2014 13:39:12

%S 3,7,13,15,25,27,29,31,49,51,53,55,57,59,61,63,97,99,101,103,105,107,

%T 109,111,113,115,117,119,121,123,125,127,193,195,197,199,201,203,205,

%U 207,209,211,213,215,217,219,221,223,225,227,229,231,233

%N Binary expansion of n has form 11**...*1.

%C If n>3 is in the sequence so are 2n-1 and 2n+1.

%F a(n) = 2^floor(log[2](4*(n-1)))+2*n-1 for n>1, a(1)=3. - Antonio G. Astudillo (afg_astudillo(AT)hotmail.com), Feb 22 2003

%F Equals 2 * A004760(n) + 1. - _Ralf Stephan_, Sep 16 2003

%Y A004755 = union of A079946 and this sequence.

%Y A diagonal of A246830.

%K nonn

%O 1,1

%A _Benoit Cloitre_, Feb 22 2003