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 A183143 #10 Aug 28 2025 05:36:58 %S A183143 0,1,2,4,6,9,13,17,22,27,33,39,46,54,62,71,80,90,100,111,123,135,148, %T A183143 161,175,190,205,221,237,254,271,289,308,327,347,367,388,409,431,454, %U A183143 477,501,525,550,575,601,628,655,683,711,740,770,800,831 %N A183143 [1/r]+[2/r]+...+[n/r], where r=sqrt(3) and []=floor. %C A183143 A183143 + A183144 = A000217 (the triangular numbers). %F A183143 [1/r]+[2/r]+...+[n/r], where r=sqrt(3) and []=floor. %p A183143 A183143 := proc(n) %p A183143 local r; %p A183143 r := sqrt(3) ; %p A183143 add( floor(i/r),i=1..n) ; %p A183143 end proc: %p A183143 seq( A183143(n),n=1..200) ; # _R. J. Mathar_, Aug 28 2025 %t A183143 Accumulate[Floor[Range[60]/Sqrt[3]]] (* _Harvey P. Dale_, Sep 10 2019 *) %o A183143 (PARI) default(realprecision,100); r=sqrt(3); for(n=1,99,print1(sum(k=1,n,floor(k/r)),", ")) %Y A183143 Cf. A183142, A183144, A183136. %K A183143 nonn,changed %O A183143 1,3 %A A183143 _Clark Kimberling_, Dec 26 2010