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 A322045 #9 Mar 07 2025 02:55:54
%S A322045 10,15,21,28,36,45,55,66,78,91,5050,5151
%N A322045 Triangular numbers that are 2-digit-repblocks.
%H A322045 Bir Kafle, Florian Luca, and Alain Togbé, <a href="https://www.fq.math.ca/Papers1/56-4/kafle1022018.pdf">Triangular repblocks</a>, The Fibonacci Quarterly, 56:4 (2018), 325-328.
%t A322045 Select[Union[Flatten[Table[FromDigits[PadRight[{}, n, k], 100], {n, 3}, {k, 10, 99}]]], IntegerQ[Sqrt[8*# + 1]] &] (* _Amiram Eldar_, Mar 07 2025, after _Harvey P. Dale_ at A045914 *)
%Y A322045 Cf. A000217, A010785, A045914.
%K A322045 nonn,fini,full,base
%O A322045 1,1
%A A322045 _N. J. A. Sloane_, Dec 07 2018