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%I #18 Sep 08 2022 08:44:57
%S 1,17,258,3874,58115,871731,13075972,196139588,2942093829,44131407445,
%T 661971111686,9929566675302,148943500129543,2234152501943159,
%U 502684312937210790,113103970410872427766,25448393342446296247367
%N Take the first n numbers written in base 15, concatenate them, then convert from base 15 to base 10.
%H Vincenzo Librandi, <a href="/A048446/b048446.txt">Table of n, a(n) for n = 1..200</a>
%e a(14) = (1)(2)(3)(4)(5)(6)(7)(8)(9)(A)(B)(C)(D)(E) = 123456789ABCDE_15 = 2234152501943159.
%t If[STARTPOINT==1, n={}, n=Flatten[IntegerDigits[Range[STARTPOINT-1], 15]]]; Table[AppendTo[n, IntegerDigits[w, 15]]; n=Flatten[n]; FromDigits[n, 15], {w, STARTPOINT, ENDPOINT}] (* _Dylan Hamilton_, Aug 11 2010 *)
%t f[n_]:= FromDigits[Flatten@IntegerDigits[Range@n, 15], 15]; Array[f, 20] (* _Vincenzo Librandi_, Dec 30 2012 *)
%o (Magma) [n eq 1 select 1 else Self(n-1) * 15^(1+Ilog(15, n)) + n: n in [1..20]]; // _Vincenzo Librandi_, Dec 30 2012
%Y Cf. A014898.
%Y 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: A048443, 13: A048444, 14: A048445, 15: this sequence, 16: A048447.
%K nonn,base,easy
%O 1,2
%A _Patrick De Geest_, May 15 1999
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