A248711 Concatenations of three numbers A,R,B where R=A+B or R=A-B or R=A*B or R=A/B.

100, 101, 110, 111, 121, 122, 132, 133, 143, 144, 154, 155, 165, 166, 176, 177, 187, 188, 198, 199, 200, 202, 211, 212, 220, 221, 231, 242, 253, 263, 264, 275, 284, 286, 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

Offset: 1

Author

Eric Angelini and M. F. Hasler, Oct 11 2014

Keywords

• nonn
• base

Comments

It is understood that none of A,R,B may have leading zeros.

Terms 101 < a(n) < 200 are exactly the numbers in that range which are in A112651.

Examples

			a(1) = 100 = concat(1,1*0,0).
The first 4-digit terms are 1000 = concat(10,10*0,0), 1019 = concat(10,10-9,9), 1025 = concat(10,10/5,5).
		

Links

• E. Angelini and J. Tramu, DigIt, 2013

Crossrefs

Cf. A112651.

Programs

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)}