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URL: https://oeis.org/A048438

⇱ A048438 - OEIS

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A048438
Take the first n numbers written in base 6, concatenate them, then convert from base 6 to base 10.
17
1, 8, 51, 310, 1865, 67146, 2417263, 87021476, 3132773145, 112779833230, 4060073996291, 146162663866488, 5261855899193581, 189426812370968930, 6819365245354881495, 245497148832775733836, 8837897357979926418113, 318164304887277351052086, 11453914975941984637875115
OFFSET
1,2
COMMENTS
The first three primes in this sequence occur for n = 11 (a(11) = 4060073996291), n = 43 (a(43) = 4.3194...*10^68), n = 173 (a(n) = 1.3014...*10^372) (email from Kurt Foster, Oct 24 2015). - N. J. A. Sloane, Oct 25 2015
LINKS
EXAMPLE
a(8) = (1)(2)(3)(4)(5)(10)(11)(12) = 12345101112_6 = 87021476.
MATHEMATICA
If[STARTPOINT==1, n={}, n=Flatten[IntegerDigits[Range[STARTPOINT-1], 6]]]; Table[AppendTo[n, IntegerDigits[w, 6]]; n=Flatten[n]; FromDigits[n, 6], {w, STARTPOINT, ENDPOINT}] (* Dylan Hamilton, Aug 11 2010 *)
Table[FromDigits[Flatten[IntegerDigits[#, 6]&/@Range[n]], 6], {n, 20}] (* Harvey P. Dale, Sep 29 2012 *)
PROG
(Magma) [n eq 1 select 1 else Self(n-1)*6^(1+Ilog(6, n))+n: n in [1..20]]; // Vincenzo Librandi, Dec 30 2012
CROSSREFS
Cf. A014829.
Concatenation of first n numbers in other bases: 2: A047778, 3: A048435, 4: A048436, 5: A048437, 6: this sequence, 7: A048439, 8: A048440, 9: A048441, 10: A007908, 11: A048442, 12: A048443, 13: A048444, 14: A048445, 15: A048446, 16: A048447.
Sequence in context: A383948 A055147 A014829 * A348312 A295602 A226199
KEYWORD
nonn,base,easy
AUTHOR
Patrick De Geest, May 15 1999
STATUS
approved