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 A194080 #37 Jul 07 2015 22:24:49
%S A194080 1,3,6,45,2775,239778,3293461,3815703,8142176137578,25025955346953,
%T A194080 27262684236385,2430563686654005,17543349622599580,95966329187365806,
%U A194080 69152680331115315990,130831703828369011153,10553338813847920825078,120456843371021570368956
%N A194080 Partial sums of the squarefree integers that are triangular.
%C A194080 For the partial sum to the squarefree integer: 1, 2, 3, 11, 94, 890, 3290, 3538, 5175587, 9073717, 9470490, 89421695, 240240143, ..., .
%C A194080 No more terms in the first 4*10^11 partial sums. - _Donovan Johnson_, Feb 20 2012
%t A194080 triQ[n_] := IntegerQ@ Sqrt[ 8n + 1]; k = 1; s = 0; lst = {}; While[k < 3*10^8, If[ SquareFreeQ@ k, s = s + k; If[ triQ@ s, AppendTo[lst, s]; Print[{k, s}]]]; k++]
%Y A194080 Cf. A005117, A173143.
%K A194080 nonn
%O A194080 1,2
%A A194080 _Robert G. Wilson v_, Aug 19 2011
%E A194080 a(14)-a(16) from _Donovan Johnson_, Aug 24 2011
%E A194080 a(17)-a(18) from _Donovan Johnson_, Feb 20 2012