Search: id:A072443
Results 1-1 of 1 results found.

%I A072443
%S A072443 252,403,574,736,765,976,1008,1207,1300,1458,1462,1612,1729,1855,1944,
%T A072443 2268,2296,2430,2668,2701,2944,3154,3478,3627,3640,4032,4275,4606,4930,
%U A072443 5092,5605,5848,6624,6786,7663,8722,11110,12240,13390,13552,14560
%N A072443 Nonsquares which are the product of two numbers with the same digits 
               (leading zeros are forbidden).
%D A072443 P. Vaderlind, R. K. Guy and L. C. Larsen, The Inquisitive Problem Solver, 
               Math. Assoc. Am., 2002, Problem P185.
%e A072443 12*21 = 252 = 12*21, 403 = 13*31, 574 = 14*41, etc
%o A072443 (PARI) {for(n=100,15000,k=floor(log(n)/log(100)); f=divisors(n); v=[]; 
               for(h=1,matsize(f)[2], if(10^k<f[h]&&f[h]<10^(k+1),v=concat(v,f[h]))); 
               b=matsize(v)[2]; if(b>1, w=[]; for(i=1,b,s=[]; a=v[i]; while(a>0,
               d=divrem(a,10); a=d[1]; s=concat(d[2],s)); w=concat(w,[vecsort(s)])); 
               c=0; for(i=1,b-1, for(j=i+1,b,if(c<1&&w[i]==w[j],if(v[i]*v[j]==n,
               print1(n,","); c=1))))))}
%Y A072443 A076750 and A077760 are subsequences.
%Y A072443 Sequence in context: A046331 A066695 A104396 this_sequence A129623 A062904 
               A032800
%Y A072443 Adjacent sequences: A072440 A072441 A072442 this_sequence A072444 A072445 
               A072446
%K A072443 base,nonn
%O A072443 1,1
%A A072443 N. J. A. Sloane (njas(AT)research.att.com), Nov 11 2002
%E A072443 Extended by Klaus Brockhaus (klaus-brockhaus(AT)t-online.de), Nov 12 
               2002

Search completed in 0.001 seconds