OFFSET
1,2
COMMENTS
Number of digits of the concatenated first n entries of A007908.
EXAMPLE
Example: The 4th number is 10, because the number of digits in the concatenation 1121231234 is 10.
MATHEMATICA
t=Table[n*(n+1)/2, {n, 53}]; q=9; Add12[l_]:=Table[l[[n+q]]+l[[n]], {n, Length[l]-q}]; Join[Take[t, 9], Add12[t]] (* Vladimir Joseph Stephan Orlovsky, Feb 01 2012 *)
PROG
(Other) Visual Basic: Function Number(ByVal n As Long) Dim i As Long, b() ReDim b(n) For i = 1 To n b(i) = b(i - 1) + Len(CStr(i)) Number = Number + b(i) Next End Function
CROSSREFS
KEYWORD
easy,base,nonn
AUTHOR
Zhining Yang, Sep 05 2009
EXTENSIONS
Edited and extended by R. J. Mathar, Sep 06 2009
STATUS
approved