Search: id:A077441
Results 1-1 of 1 results found.

%I A077441
%S A077441 0,4,7,26,28,127,306,348,398,301,308,203,311,783,294,350,199,296,4268,
%T A077441 16595,5326,4253,17399,8235,6189,4270,3107,1270,1532,511,67816,65975,
%U A077441 24670,12395,4282,3119,28799,16861,18164,66268,45087,71164,309234
%N A077441 In base 4, smallest number which requires n Reverse and Add! steps to 
               reach a palindrome.
%C A077441 Base-4 analogue of A066058 (base 2) and A023109 (base 10).
%H A077441 <a href="Sindx_Res.html#RAA">Index entries for sequences related to Reverse 
               and Add!</a>
%e A077441 7 is the smallest number which requires two steps to reach a base 4 palindrome 
               (cf. A075685), so a(2) = 5; 7 (decimal) = 13 -> 13 + 31 = 110 -> 
               110 + 011 = 121 (palindrome) = 25 (decimal).
%o A077441 (PARI) {m=46; v=[]; for(j=1,m+1,v=concat(v,-1)); mc=m+1; n=0; while(mc>
               0,a=-1; c=0; k=n; while(c<m+1,q=k; rev=0; while(q>0,d=divrem(q,4); 
               q=d[1]; rev=4*rev+d[2]); if(k==rev,a=c; c=m+1,c++; k=k+rev)); if(0<=a&&a<=m,
               if(v[a+1]<0,v[a+1]=n; mc--; print1([a,n]))); n++); print(); for(j=1,
               m+1,print1(v[j],","))}
%Y A077441 Cf. A075685, A066058, A023109.
%Y A077441 Sequence in context: A151348 A110413 A075686 this_sequence A076148 A146085 
               A061668
%Y A077441 Adjacent sequences: A077438 A077439 A077440 this_sequence A077442 A077443 
               A077444
%K A077441 base,nonn
%O A077441 0,2
%A A077441 Klaus Brockhaus (klaus-brockhaus(AT)t-online.de), Nov 05 2002

Search completed in 0.001 seconds