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 A183227 a(n) is the base-5 digit sum of 10^n-1. 3

%I #12 Jan 06 2019 04:55:01

%S 0,5,11,15,19,23,31,31,35,43,51,55,59,63,63,71,79,87,91,95,95,95,107,

%T 115,123,119,135,139,135,147,159,163,159,155,163,171,175,187,179,191,

%U 195,203,211,211,211,219,219,231,235,239

%N a(n) is the base-5 digit sum of 10^n-1.

%F a(n) = A053824(10^n-1) = 4*n + A053824(2^n-1).

%e a(9) = 43 because 10^9 - 1 is written as 4021444444444_5, and 2^9 - 1 = 511 is written as 4021_5.

%p A053824 := proc(n) add(d,d=convert(n,base,5)) ; end proc:

%p A183227 := proc(n) A053824(10^n-1) ; end proc: # _R. J. Mathar_, Jan 09 2011

%o (PARI)\\L is a list of the N digits of 2^n - 1 in quinary

%o convert(n)={n = 2^n - 1; x=n; N=floor(log(n)/log(5))+1;

%o L = listcreate(N);

%o while(x, n=floor(n/5); r=x-5*n; listput(L, r); x=n; );

%o L; N};

%o print1("0, "); for(n = 1,100, convert(n); s = 0; for(i = 1, N, s += L[i];); print1(s+4*n, ", "));

%Y Cf. A183226, A183228.

%K nonn,easy,base

%O 0,2

%A _Washington Bomfim_, Jan 01 2011

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Last modified September 13 08:45 EDT 2024. Contains 375904 sequences. (Running on oeis4.)