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Search: id:A014886
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| A014886 |
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n is equal to the number of 2's in all numbers <= n written in base 8. |
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+0
8
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| 679922, 679923, 679924, 679925, 679926, 679927, 679928, 679929, 1048576, 16777216, 17457138, 17457139, 17457140, 17457141, 17457142, 17457143, 17457144, 17457145, 17825792
(list; graph; listen)
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OFFSET
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1,1
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PROGRAM
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(Perl) ($s, $t, $u)=(0, '1', 1); while($s <= $u*8){print "$u " if $s == $u; ($p, $o)=
(Perl) (1, 0); $q=($t =~ /^(7*)/ && length $1); $r=length($t)+1; ++$o, $p *= 8 while
(Perl) $o+1 <= $q && $p*$r*8 <= abs($u-$s); $u += $p; s/^(7*)(.)?/(0 x length($1))
(Perl) .($2+1)/e, $s += tr/2/2/*$p + $o*$p/8 for substr $t, $o } print "\n"
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CROSSREFS
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Cf. A014778.
Sequence in context: A068246 A068248 A119404 this_sequence A010095 A081415 A101698
Adjacent sequences: A014883 A014884 A014885 this_sequence A014887 A014888 A014889
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KEYWORD
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nonn,base,fini,full
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AUTHOR
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Olivier Gerard (olivier.gerard(AT)gmail.com)
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EXTENSIONS
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More terms and Perl program from Hugo van der Sanden (hv(AT)crypt.org)
Comment from Hugo van der Sanden: Program terminates at n = 2.94239143846251e+56, when 2.37843307942386e+57 2's have been seen; since s > 8n and n > 8^8 at this point, it is not possible for n ever again to catch up with the sum (given s(8^n) = n 8^{n-1}).
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