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Nonnegative integers that can be computed using exactly ten 10's and the four basic arithmetic operations {+, -, *, /}.
14

%I #14 Aug 31 2015 20:34:14

%S 0,1,2,3,4,5,6,7,8,9,10,11,12,13,14,15,16,17,18,19,20,21,22,23,24,25,

%T 26,27,28,29,30,31,32,33,34,35,36,37,38,39,40,41,42,43,44,45,46,47,48,

%U 49,50,51,52,53,54,55,56,57,58,59,60,61,62,63,64,65,66,67

%N Nonnegative integers that can be computed using exactly ten 10's and the four basic arithmetic operations {+, -, *, /}.

%C The smallest non-computable number here is 443. The largest computable number here is 10^10 = 10000000000.

%H Alois P. Heinz, <a href="/A258071/b258071.txt">Table of n, a(n) for n = 1..15945</a>

%p f:= proc(n) f(n):= `if`(n=1, {10}, {seq(seq(seq([x+y, x-y, x*y,

%p `if`(y=0, [][], x/y)][], y=f(n-j)), x=f(j)), j=1..n-1)})

%p end:

%p sort([select(z->z>=0 and is(z, integer), f(10))[]])[];

%Y Cf. A171826, A171827, A171828, A171829, A258068, A258069, A258070.

%Y Cf. A182002, A258097.

%K nonn,look,fini,full

%O 1,3

%A _Alois P. Heinz_, May 18 2015