A275624 - OEIS

%I #8 Aug 17 2016 06:56:10

%S 4,6,8,9,14,20,24,28,31,34,37,40,42,45,47,49,51,53,55,56,58,60,62,63,

%T 65,66,68,69,71,72,73,75,76,77,79,80,81,82,84,85,86,87,88,89,90,92,93,

%U 94,95,96,97,98,99,104,113,122,130,137,144,151,157,164,170

%N a(n) = minimal m such that Sum_{k=1..m} 0.k >= n.

%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="/A275624/b275624.txt">Table of n, a(n) for n = 1..20000</a>

%e a(7) = 20 because .1 + .2 + ... + .9 + .10 + .11 + ... + .20 = 141/20 = 7.05 is the first time the sum reaches 7.

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

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

%p     end:

%p a:= proc(n) option remember; local k; for k from

%p       `if`(n=1, 1, a(n-1)) while b(k)<n do od; k

%p     end:

%p seq(a(n), n=1..100);  # _Alois P. Heinz_, Aug 17 2016

%Y Cf. A054464, A275623.

%K nonn,base

%O 1,1

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

%E More terms from _Alois P. Heinz_, Aug 17 2016