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 A048443 #23 Jun 13 2025 10:49:43
%S A048443 1,14,171,2056,24677,296130,3553567,42642812,511713753,6140565046,
%T A048443 73686780563,10610896401084,1527969081756109,220027547772879710,
%U A048443 31683966879294678255,4562491230618433668736,656998737209054448298001,94607818158103840554912162
%N A048443 Take the first n numbers written in base 12, concatenate them, then convert from base 12 to base 10.
%H A048443 Vincenzo Librandi, <a href="/A048443/b048443.txt">Table of n, a(n) for n = 1..200</a>
%e A048443 a(12) = (1)(2)(3)(4)(5)(6)(7)(8)(9)(A)(B)(10) = 123456789AB10_12 = 10610896401084.
%t A048443 If[STARTPOINT==1, n={}, n=Flatten[IntegerDigits[Range[STARTPOINT-1], 12]]]; Table[AppendTo[n, IntegerDigits[w, 12]]; n=Flatten[n]; FromDigits[n, 12], {w, STARTPOINT, ENDPOINT}] (* _Dylan Hamilton_, Aug 11 2010 *)
%t A048443 f[n_]:= FromDigits[Flatten@IntegerDigits[Range@n, 12], 12]; Array[f, 20] (* _Vincenzo Librandi_, Dec 30 2012 *)
%o A048443 (Magma) [n eq 1 select 1 else Self(n-1)*12^(1+Ilog(12, n))+n: n in [1..20]]; // _Vincenzo Librandi_, Dec 30 2012
%Y A048443 Cf. A014882.
%Y A048443 Concatenation of first n numbers in other bases: 2: A047778, 3: A048435, 4: A048436, 5: A048437, 6: A048438, 7: A048439, 8: A048440, 9: A048441, 10: A007908, 11: A048442, 12: this sequence, 13: A048444, 14: A048445, 15: A048446, 16: A048447.
%K A048443 nonn,base,easy
%O A048443 1,2
%A A048443 _Patrick De Geest_, May 15 1999