cp's OEIS Frontend

A062129 In base 2: start with n; add to itself with digits reversed; if palindrome, stop; otherwise repeat; a(n) gives palindrome at which it stops, or -1 if no palindrome is ever reached.

%I A062129 #10 Apr 19 2025 14:38:49
%S A062129 0,11,11,1001,101,1111,1001,10101,1001,11011,1111,11011,1111,11011,
%T A062129 10101,101101,10001,110011,11011,1100011,1100011,111111,-1,111111,
%U A062129 11011,1100011,-1,11111111,-1,111111,101101,1011101,100001,1100011,110011,-1,101101,-1,111111,1100011,101101,-1,111111
%N A062129 In base 2: start with n; add to itself with digits reversed; if palindrome, stop; otherwise repeat; a(n) gives palindrome at which it stops, or -1 if no palindrome is ever reached.
%C A062129 The analog of A061563 in base 2. Differs from A062128 only for those n, which are palindromes in base 2.
%e A062129 23: 10111 -> 10111 + 11101 = 110100 -> 110100 + 1011 = 111111, so a(23) = 111111.
%o A062129 (ARIBAS) stop := 500; for k := 0 to 60 do c := 0; m := k; test := true; while test and c < stop do inc(c); m := m + bit_reverse(m); test := m <> bit_reverse(m); end; if c < stop then bit_write(m); else write(-1); end; write(" "); end;
%Y A062129 Cf. A061563, A062128, A062131, A058042.
%K A062129 base,easy,sign
%O A062129 0,2
%A A062129 _Klaus Brockhaus_, Jun 06 2001