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A014886 n is equal to the number of 2's in all numbers <= n written in base 8. 7
679922, 679923, 679924, 679925, 679926, 679927, 679928, 679929, 1048576, 16777216, 17457138, 17457139, 17457140, 17457141, 17457142, 17457143, 17457144, 17457145, 17825792 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

LINKS

Table of n, a(n) for n=1..19.

PROG

(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"

CROSSREFS

Cf. A014778.

Sequence in context: A237005 A205244 A119404 * A253868 A253875 A253541

Adjacent sequences:  A014883 A014884 A014885 * A014887 A014888 A014889

KEYWORD

nonn,base,fini,full

AUTHOR

Olivier Gérard

EXTENSIONS

More terms and Perl program from Hugo van der Sanden

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}).

STATUS

approved

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Last modified September 24 06:13 EDT 2021. Contains 347623 sequences. (Running on oeis4.)