OFFSET
1,1
EXAMPLE
a(3)=489 because the first 3 multiples of 3 in binary are 11 110 1001, and the concatenation 111101001 in base 10 = 489. a(4)=7836 because the first 4 3 multiples of 3 in binary are 11 110 1001 1100, and the concatenation 1111010011100 in base 10 = 7836.
MATHEMATICA
Module[{nn=20, tb}, tb=IntegerDigits[3*Range[nn], 2]; Table[FromDigits[ Flatten[ Take[tb, n]], 2], {n, nn}]] (* Harvey P. Dale, Oct 11 2017 *)
CROSSREFS
KEYWORD
base,easy,nonn
AUTHOR
Gil Broussard, Sep 01 2009
STATUS
approved