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 A068132 #12 Sep 19 2024 16:34:00 %S A068132 5995,14878,17578,24976,29890,32896,36856,37675,42778,47278,52975, %T A068132 53956,54946,55945,56953,57970,67528,68635,69751,70876,75466,76636, %U A068132 77815,83845,85078,87571,88831,91378,92665,93961,95266,96580,97903 %N A068132 Triangular numbers with sum of digits = 28. %C A068132 The sequence is unbounded, as the (10^k + 9)-th triangular number for k>1 is a term. %C A068132 The sum of the digits of triangular numbers in most cases is a triangular number. %C A068132 Conjecture: For every triangular number T there exist infinitely many triangular numbers with sum of digits = T. %t A068132 Select[Accumulate[Range[500]],Total[IntegerDigits[#]]==28&] (* _Harvey P. Dale_, Aug 30 2015 *) %Y A068132 Subsequence of A000217. %Y A068132 Cf. A068127, A068128, A068129, A068130, A068131. %K A068132 base,easy,nonn %O A068132 1,1 %A A068132 _Amarnath Murthy_, Feb 21 2002 %E A068132 More terms from _Sascha Kurz_, Mar 06 2002 %E A068132 Offset changed by _Andrew Howroyd_, Sep 19 2024