OFFSET
0,22
COMMENTS
LINKS
T. D. Noe, Table of n, a(n) for n = 0..1000
EXAMPLE
a(21) = 2 because 21 (base 10) = 111 (base 4), whose first two digits are 1's, and whose rightmost two digits are the second substring of "11".
MAPLE
A196272 := proc(n)
local a, dgs ;
a := 0 ;
dgs := convert(n, base, 4) ;
for i from 1 to nops(dgs)-1 do
if op(i, dgs)=1 and op(i+1, dgs)=1 then
a := a+1 ;
end if;
end do;
a ;
end proc:
seq(A196272(n), n=0..100) ; # R. J. Mathar, Sep 30 2011
MATHEMATICA
Table[d = IntegerDigits[n, 4]; Count[Partition[d, 2, 1], {1, 1}], {n, 0, 100}] (* T. D. Noe, Sep 30 2011 *)
CROSSREFS
KEYWORD
nonn,easy,base
AUTHOR
Jonathan Vos Post, Sep 29 2011
STATUS
approved