A275625 - OEIS

%I #13 Sep 15 2023 18:18:28

%S 1,3,3,1,3,21,14,18,9,23,471,483,124,51,21,541,279,144,119,123,159,

%T 329,681,141,73,189,783,811,42,87,901,933,483,10,207,1071,277,573,237,

%U 49,633,327,1351,279,72,743,1533,1581,163,84,1731,1783,459,189,389,2001,1029,529,87,447,574,1179

%N Numerator of Sum_{k=1..n} 0.k.

%C Here 0.k means the decimal fraction obtained by writing k after the decimal point, e.g. 0.12 = 12/100 = 3/25.

%H Alois P. Heinz, <a href="/A275625/b275625.txt">Table of n, a(n) for n = 1..20000</a>

%e The first few values of Sum_{k=1..n} 0.k are:

%e 1/10, 3/10, 3/5, 1, 3/2, 21/10, 14/5, 18/5, 9/2, 23/5, 471/100, 483/100, 124/25, 51/10, 21/4, 541/100, 279/50, 144/25, 119/20, 123/20, 159/25, 329/50, 681/100, 141/20, 73/10, 189/25, ...

%p b:= proc(n) option remember;

%p        n/10^length(n)+`if`(n<2, 0, b(n-1))

%p     end:

%p a:= n-> numer(b(n)):

%p seq(a(n), n=1..100);  # _Alois P. Heinz_, Aug 16 2016

%Y Cf. A275626, A054464, A275623, A275624.

%K nonn,base,look,frac

%O 1,2

%A _N. J. A. Sloane_, Aug 07 2016