

A196096


Occurrences of '11' in base 3 expansion of n.


2



0, 0, 0, 0, 1, 0, 0, 0, 0, 0, 0, 0, 1, 2, 1, 0, 0, 0, 0, 0, 0, 0, 1, 0, 0, 0, 0, 0, 0, 0, 0, 1, 0, 0, 0, 0, 1, 1, 1, 2, 3, 2, 1, 1, 1, 0, 0, 0, 0, 1, 0, 0, 0, 0, 0, 0, 0, 0, 1, 0, 0, 0, 0, 0, 0, 0, 1, 2, 1, 0, 0, 0, 0, 0, 0, 0, 1, 0, 0, 0, 0, 0, 0, 0, 0, 1
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OFFSET

0,14


COMMENTS



LINKS



EXAMPLE

a(4) = 1 because 4 in base 3 is "11" which has one instance of "11".
a(13) = 2 because the number 13 in base 3 is "111" which has two substrings of "11".


MAPLE

local a, dgs3 ;
a := 0 ;
dgs3 := convert(n, base, 3) ;
for i from 1 to nops(dgs3)1 do
if op(i, dgs3)=1 and op(i+1, dgs3)=1 then
a := a+1 ;
end if;
end do;
a ;
end proc:


MATHEMATICA

f[n_] := Count[ Partition[ IntegerDigits[ n, 3], 2, 1], {1, 1}]; Array[f, 100, 0] (* Robert G. Wilson v, Sep 27 2011 *)


CROSSREFS



KEYWORD

easy,nonn


AUTHOR



STATUS

approved



