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A089601
Interleaving of A089591 and A089600.
2
0, 0, 1, 1, 2, 10, 11, 11, 12, 20, 21, 101, 102, 110, 111, 111, 112, 120, 121, 201, 202, 210, 211, 1011, 1012, 1020, 1021, 1101, 1102, 1110, 1111, 1111, 1112, 1120, 1121, 1201, 1202, 1210, 1211, 2011, 2012, 2020, 2021, 2101, 2102, 2110, 2111, 10111
OFFSET
0,5
FORMULA
To get a(n), drop last digit from either A089591(n) or A089600(n+1).
MAPLE
A089591 := proc(n) option remember ; local nhalf ; if n <= 1 then RETURN(n) ; else nhalf := floor(n/2) ; if n mod 2 = 1 then RETURN(10*A089591(nhalf) +1) ; else RETURN(10*(A089591(nhalf-1)+1)) ; fi ; fi ; end: A089600 := proc(n) option remember ; local nhalf ; nhalf := floor(n/2) ; if n <= 1 then RETURN(n) ; else if n mod 2 = 1 then RETURN(10*A089600(nhalf) +1) ; else RETURN(10*A089591(nhalf-1)+2) ; fi ; fi ; end: A089601 := proc(n) if n mod 2 = 0 then A089600(n/2) ; else A089591((n-1)/2) ; fi ; end: seq(A089601(n), n=0..80) ; # R. J. Mathar, Jul 20 2007
CROSSREFS
Sequence in context: A222638 A299982 A367638 * A171893 A278816 A043072
KEYWORD
nonn,easy,base
AUTHOR
Jeff Erickson, Dec 31 2003
EXTENSIONS
More terms from R. J. Mathar, Jul 20 2007
STATUS
approved