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 A371060 #8 Mar 12 2024 23:44:50
%S A371060 1,2,21,22,3,4,5,6,7,8,9,28,72,65,24,32,23,31,33,13,34,25,42,43,35,36,
%T A371060 44,14,41,441,442,45,26,52,54,46,37,53,55,15,51,551,552,56,27,62,66,
%U A371060 16,61,661,662,67,38,63,57,39,73,64,47,48,58,49,68,59,69,74,75,76,77,17,71,771,772
%N A371060 Lexicographically earliest sequence of distinct terms such that every triplet of successive digits (seen as side lengths) can form a triangle.
%C A371060 In a triangle, the sum of any two side lengths is greater than that of the third, so that x + y > z.
%H A371060 Eric Angelini and Giorgos Kalogeropoulos, <a href="https://cinquantesignes.blogspot.com/2024/03/triangles-with-digits.html">Triangles with digits</a>, Personal blog, March 2024.
%e A371060 The first triplet of digits (1, 2, 2) forms an isosceles triangle with basis 1 and sides 2 and 2;
%e A371060 the second triplet (2, 2, 1) forms another isosceles triangle with basis 1 and sides 2 and 2;
%e A371060 the fifth triplet (2, 2, 3) forms another isosceles triangle with basis 3 and sides 2 and 2;
%e A371060 the sixth triplet (2, 3, 4) forms a scalene triangle with sides 2, 3 and 4; etc.
%t A371060 g[1]=1;g[2]=2;g[n_]:=g[n]=(k=1;While[MemberQ[ar=Array[g,n-1],k]|| !And@@(({a,b,c}=#;And@@{a+b>c,b+c>a,a+c>b})&/@Partition[Flatten[IntegerDigits/@Join[ar,{k}]],3,1]),k++];k);Array[g,80]
%Y A371060 Cf. A370408.
%K A371060 base,nonn
%O A371060 1,2
%A A371060 _Eric Angelini_ and _Giorgos Kalogeropoulos_, Mar 09 2024