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%I #10 Dec 18 2019 10:58:42

%S 0,1,2,3,4,5,6,7,8,9,10,11,12,13,14,105,106,107,108,109,20,21,22,23,

%T 24,205,206,207,208,209,30,31,32,33,34,305,306,307,308,309,40,41,42,

%U 43,44,405,406,407,408,409,50,51,52,53,54,505,506,507

%N A322131/2.

%H Rémy Sigrist, <a href="/A330336/b330336.txt">Table of n, a(n) for n = 0..10000</a>

%F a(n) >= n with equality iff all the digits of the decimal representation of n, except possibly the first one, are in the range 0...4. - _Rémy Sigrist_, Dec 18 2019

%p a:= n-> (s-> parse(cat(seq(parse(s[i])*2, i=1..length(s))))/2)(""||n):

%p seq(a(n), n=0..70); # _Alois P. Heinz_, Dec 18 2019

%o (PARI) a(n, base=10) = my (d=digits(n, base), v=0); for (i=1, #d, v = v*base^max(1, #digits(2*d[i], base)) + 2*d[i]); v/2 \\ _Rémy Sigrist_, Dec 18 2019

%Y Cf. A322131.

%K nonn,base

%O 0,3

%A _N. J. A. Sloane_, Dec 17 2019