Search: id:A030152
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%I A030152
%S A030152 0,1,4,9,16,25,36,49,81,121,169,256,361,529,676,729,961,1296,4761,5476,
%T A030152 6561,7056,9216,12321,12769,14161,16129,18769,32761,34969,41616,56169,
%U A030152 69696,72361,74529,76729,78961,87616,96721,147456,163216,181476,212521
%N A030152 Squares in which parity of digits alternates.
%e A030152 1296 is a term as 1, 2, 9 and 6 have odd and even parity alternately.
%p A030152 i := 0:for a from 1 to 1000 do b := a^2:g := ceil(log(b+1)/log(10)):iss 
               := true:for j from 1 to g-1 do if((b mod 2)=1) then if((floor(b/10^j) 
               mod 2)=((-1)^(j+1)+1)/2) then iss := false:end if:else if((floor(b/
               10^j) mod 2)=((-1)^j+1)/2) then iss := false:end if:end if:end do: 
               if(iss=true) then i := i+1:c[i] := b:end if:end do:q := seq(c[k],
               k=1..i-1); - Sascha Kurz (sascha.kurz(AT)uni-bayreuth.de), Mar 23 
               2002
%Y A030152 Cf. A030144.
%Y A030152 Sequence in context: A110723 A084617 A068879 this_sequence A030288 A030154 
               A122541
%Y A030152 Adjacent sequences: A030149 A030150 A030151 this_sequence A030153 A030154 
               A030155
%K A030152 nonn,base
%O A030152 0,3
%A A030152 Patrick De Geest (pdg(AT)worldofnumbers.com)
%E A030152 Edited by N. J. A. Sloane, Aug 31 2009 at the suggestion of R. J. Mathar

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