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A077403 In base 3: smallest number that requires n Reverse and Add! steps to reach a palindrome.

%I A077403 #7 Jul 11 2015 00:42:35
%S A077403 0,3,5,15,17,263,170,509,491,322,266,222,161,494,260,106,95,78,53,
%T A077403 2425,1466,9717,59583,38878,38798,33515,39440,32857,37340,238849,
%U A077403 177470,60019,59655,178540,124895,59753,179751,1595576,715615,354605,179575
%N A077403 In base 3: smallest number that requires n Reverse and Add! steps to reach a palindrome.
%C A077403 Base 3 analog of A066058 (base 2), A077441 (base 4) and A023109 (base 10).
%H A077403 <a href="/index/Res#RAA">Index entries for sequences related to Reverse and Add!</a>
%e A077403 5 is the smallest number which requires two steps to reach a base 3 palindrome (cf. A066057), so a(2) = 5; 5 (decimal) = 12 -> 12 + 21 = 110 -> 110 + 011 = 121 (palindrome) = 16 (decimal).
%o A077403 (ARIBAS) var ar: array; end; m := 45; ar := alloc(array, m+1, -1); mc := m+1; n := 0; while mc > 0 do v := -1; c := 0; k := n; while c < m+1 do d := k; rev := 0; while d > 0 do rev := 3*rev+(d mod 3); d := d div 3; end; if k = rev then v := c; c := m+1; else inc(c); k := k+rev; end; end; if 0 <= v and v <= m then if ar[v] < 0 then ar[v] := n; dec(mc); write((v,n)); end; end; inc(n); end; writeln(); for j := 0 to m do write(ar[j],","); end;
%Y A077403 Cf. A066057, A066058, A077441, A023109.
%K A077403 base,nonn
%O A077403 0,2
%A A077403 _Klaus Brockhaus_, Nov 05 2002