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 A083678 #23 Jul 29 2025 00:21:21
%S A083678 19,28,37,46,55,64,73,82,91,1199,1289,1379,1469,1559,1649,1739,1829,
%T A083678 1919,2198,2288,2378,2468,2558,2648,2738,2828,2918,3197,3287,3377,
%U A083678 3467,3557,3647,3737,3827,3917,4196,4286,4376,4466,4556,4646,4736,4826,4916
%N A083678 Numbers m = d_1 d_2 ... d_k (in base 10) with properties that k is even and d_i + d_{k+1-i} = 10 for all i.
%C A083678 The two-digit terms here occur in many sequences, e.g., A066686, A081926, A017173, A030108, A043457, A052224, A061388, A084364.
%H A083678 Harvey P. Dale, <a href="/A083678/b083678.txt">Table of n, a(n) for n = 1..819</a> (All terms through 999999.)
%e A083678 1469 and 6284 are members because 1+9=4+6=10 and 6+4=2+8=10.
%t A083678 ok10Q[n_]:=Module[{idn=IntegerDigits[n]},idn[[1]]+idn[[4]]==idn[[2]]+idn[[3]]==10]; Join[ Select[ Range[10,99],Total[IntegerDigits[#]]==10&],Select[Range[1000,9999],ok10Q]] (* _Harvey P. Dale_, Oct 14 2023 *)
%o A083678 (PARI) isok(n) = {digs = digits(n); if (#digs % 2 == 0, for (i = 1, #digs/2, if ((digs[i] + digs[#digs+1-i]) ! = 10, return (0));); return (1);); return (0);} \\ _Michel Marcus_, Oct 05 2013
%Y A083678 Cf. A066686, A081926, A017173, A030108, A043457, A052224, A061388, A084364.
%K A083678 easy,nonn,base
%O A083678 1,1
%A A083678 _Zak Seidov_ Jun 15 2003