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Search: id:A030152
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| A030152 |
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Squares in which parity of digits alternates. |
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+0
9
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| 0, 1, 4, 9, 16, 25, 36, 49, 81, 121, 169, 256, 361, 529, 676, 729, 961, 1296, 4761, 5476, 6561, 7056, 9216, 12321, 12769, 14161, 16129, 18769, 32761, 34969, 41616, 56169, 69696, 72361, 74529, 76729, 78961, 87616, 96721, 147456, 163216, 181476, 212521
(list; graph; listen)
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OFFSET
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0,3
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EXAMPLE
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1296 is a term as 1, 2, 9 and 6 have odd and even parity alternately.
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MAPLE
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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
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CROSSREFS
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Cf. A030144.
Sequence in context: A110723 A084617 A068879 this_sequence A030288 A030154 A122541
Adjacent sequences: A030149 A030150 A030151 this_sequence A030153 A030154 A030155
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KEYWORD
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nonn,base
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AUTHOR
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Patrick De Geest (pdg(AT)worldofnumbers.com)
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EXTENSIONS
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Edited by N. J. A. Sloane, Aug 31 2009 at the suggestion of R. J. Mathar
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