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a(n) in base 14 is a repdigit.
2

%I #22 May 30 2016 18:26:19

%S 0,1,2,3,4,5,6,7,8,9,10,11,12,13,15,30,45,60,75,90,105,120,135,150,

%T 165,180,195,211,422,633,844,1055,1266,1477,1688,1899,2110,2321,2532,

%U 2743,2955,5910,8865,11820,14775,17730,20685,23640,26595,29550,32505,35460

%N a(n) in base 14 is a repdigit.

%H Vincenzo Librandi, <a href="/A048338/b048338.txt">Table of n, a(n) for n = 0..1300</a>

%H Eric Weisstein's World of Mathematics, <a href="http://mathworld.wolfram.com/Repdigit.html">Repdigit</a>

%F From _Chai Wah Wu_, May 30 2016: (Start)

%F a(n) = 15*a(n-13) - 14*a(n-26) for n > 25.

%F G.f.: x*(13*x^12 + 12*x^11 + 11*x^10 + 10*x^9 + 9*x^8 + 8*x^7 + 7*x^6 + 6*x^5 + 5*x^4 + 4*x^3 + 3*x^2 + 2*x + 1)/(14*x^26 - 15*x^13 + 1). (End)

%F a(n) = (n - 13*floor((n-1)/13))*(14^floor((n+12)/13) - 1)/13. - _Ilya Gutkovskiy_, May 30 2016

%t Union[Flatten[Table[FromDigits[PadRight[{}, n, d], 14], {n, 0, 50}, {d, 13}]]] (* _Vincenzo Librandi_, Feb 06 2014 *)

%o (Python)

%o A048338_list = [0] + [int(d*l,14) for l in range(1,10) for d in '123456789abcd'] # _Chai Wah Wu_, May 30 2016

%Y Cf. A010785, A033027, A028987, A028988.

%K nonn,base,easy

%O 0,3

%A _Patrick De Geest_, Feb 15 1999