This is a front-end for the Online Encyclopedia of Integer Sequences, made by Christian Perfect. The idea is to provide OEIS entries in non-ancient HTML, and then to think about how they're presented visually. The source code is on GitHub.
%I A165145 #11 Dec 13 2024 13:00:05
%S A165145 1,3,6,10,15,21,28,36,45,56,69,84,101,120,141,164,189,216,245,276,309,
%T A165145 344,381,420,461,504,549,596,645,696,749,804,861,920,981,1044,1109,
%U A165145 1176,1245,1316,1389,1464,1541,1620,1701,1784,1869,1956,2045,2136,2229,2324,2421
%N A165145 Partial sums of A058183.
%C A165145 Number of digits of the concatenated first n entries of A007908.
%e A165145 Example: The 4th number is 10, because the number of digits in the concatenation 1121231234 is 10.
%t A165145 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 *)
%o A165145 (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
%K A165145 easy,base,nonn
%O A165145 1,2
%A A165145 _Zhining Yang_, Sep 05 2009
%E A165145 Edited and extended by _R. J. Mathar_, Sep 06 2009