A048447 Take the first n numbers written in base 16, concatenate them, then convert from base 16 to base 10.

1, 18, 291, 4660, 74565, 1193046, 19088743, 305419896, 4886718345, 78187493530, 1250999896491, 20015998343868, 320255973501901, 5124095576030430, 81985529216486895, 20988295479420645136, 5373003642731685154833

Offset

1,2

Links

Vincenzo Librandi, Table of n, a(n) for n = 1..200

Example

a(16) = (1)(2)(3)(4)(5)(6)(7)(8)(9)(A)(B)(C)(D)(E)(F)(10) = 123456789ABCDEF10_16 = 20988295479420645136.

Mathematica

If[STARTPOINT==1, n={}, n=Flatten[IntegerDigits[Range[STARTPOINT-1], 16]]]; Table[AppendTo[n, IntegerDigits[w, 16]]; n=Flatten[n]; FromDigits[n, 16], {w, STARTPOINT, ENDPOINT}] (* Dylan Hamilton, Aug 11 2010 *)
f[n_]:= FromDigits[Flatten@IntegerDigits[Range@n, 16], 16]; Array[f, 20] (* Vincenzo Librandi, Dec 30 2012 *)

Prog

(Magma) [n eq 1 select 1 else Self(n-1)*16^(1+Ilog(16, n))+n: n in [1..20]]; // Vincenzo Librandi, Dec 30 2012
(Python)
from functools import reduce
def A048447(n): return reduce(lambda i, j:(i<<(bool((m:=j.bit_length())&3)<<2)+(m&-4))+j, range(n+1)) # Chai Wah Wu, Feb 26 2023

Crossrefs

Cf. A014899.

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: A048446, 16: this sequence.

Sequence in context: A098303 A232154 A014899 * A167713 A219670 A166927

Adjacent sequences: A048444 A048445 A048446 * A048448 A048449 A048450

Keyword

nonn,base,easy

Author

Patrick De Geest, May 15 1999

Status

approved