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 A289284 #9 Jul 24 2017 12:53:14
%S A289284 1,5,11,51,52,4,2,41,53,3,31,54,21,55,12,42,43,32,44,22,45,13,33,34,
%T A289284 23,35,14,24,25,15,16
%N A289284 Starting with a(1) = 1, a(n) = smallest nonnegative integer not yet in the sequence such that the last digit of a(n-1) plus the first digit of a(n) is equal to 6. The digit 0 is not allowed.
%C A289284 The number of terms of this finite sequence is the sixth central polygonal number, n = 31.
%t A289284 Module[{a = {1}, k, d = 6}, TimeConstrained[Do[k = 2; While[Or[MemberQ[a, k], MemberQ[IntegerDigits@ k, 0], # != d] &[Mod[a[[n - 1]], 10] + First@IntegerDigits@ k], k++]; AppendTo[a, k], {n, 2, 100}], 2]; a] (* _Michael De Vlieger_, Jul 14 2017 *)
%Y A289284 Cf. A002061, A289283.
%K A289284 nonn,base,fini,full
%O A289284 1,2
%A A289284 _Enrique Navarrete_, Jul 01 2017