A226032 - OEIS

%I #18 Oct 22 2022 08:08:23

%S 100,111,122,133,144,155,166,177,188,199,200,221,242,263,284,300,331,

%T 362,393,400,441,482,500,551,600,661,700,771,800,881,900,991,2105,

%U 2126,2147,2168,2189,3124,3155,3186,3217,3248,3279,4123,4164,4205,4246,4287,4328

%N Numbers of the form xyz, where x and z have the same number of digits and x*z = y.

%C The same digit may not be used twice as both an "outer" and "inner" digit. For example, 11211 is not in the sequence, but 1112111 is.

%C Leading zeros are not allowed.

%H Christian N. K. Anderson, <a href="/A226032/b226032.txt">Table of n, a(n) for n = 1..10000</a>

%e 482 is in the sequence because 4*2 = 8.

%e 4205 is in the sequence because 4*5 = 20.

%e 100 is in the sequence because 1*0 = 0. However, 1200 is not because even though 12*0 = 0, 12 and 0 do not have the same number of digits. Likewise, 12|0|00 and 12|00|00 are not in the sequence because leading zeros are not allowed.

%o (R)

%o y=c(); for(i in 1:9) for(j in 0:9) y=c(y, as.numeric(paste(i, i*j, j, sep=""))); sort(y)

%K nonn,base

%O 1,1

%A Alan Wing-lun, _Christian N. K. Anderson_, _Kevin L. Schwartz_, May 23 2013