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%I #12 Oct 13 2014 06:23:14
%S 100,101,110,111,121,122,132,133,143,144,154,155,165,166,176,177,187,
%T 188,198,199,200,202,211,212,220,221,231,242,253,263,264,275,284,286,
%U 297,300,303,312,313,321,330,331,341,352,362,363,374,385,393,396,400,404,413,414,422,431,440,441,451,462,473,482,484,495,500,505
%N Concatenations of three numbers A,R,B where R=A+B or R=A-B or R=A*B or R=A/B.
%C It is understood that none of A,R,B may have leading zeros.
%C Terms 101 < a(n) < 200 are exactly the numbers in that range which are in A112651.
%H E. Angelini and J. Tramu, <a href="http://www.echolalie.org/eapp/index.php">DigIt</a>, 2013
%e a(1) = 100 = concat(1,1*0,0).
%e The first 4-digit terms are 1000 = concat(10,10*0,0), 1019 = concat(10,10-9,9), 1025 = concat(10,10/5,5).
%o (PARI) is(n)={d=#digits(n);forvec(s=vector(2,i,[1,d-1]),(10^s[1]>10*B=n%10^s[1])&&s[1]>1&&next;(10^s[2]>10*R=n%10^s[2])&&s[2]>s[1]+1&&next;setsearch(Set([B+A=n\10^s[2],A-B,A*B,if(B,A/B)]),R\10^s[1])&&return([A,R\10^s[1],B]),2)}
%Y Cf. A112651.
%K nonn,base
%O 1,1
%A _Eric Angelini_ and _M. F. Hasler_, Oct 11 2014
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