Search: id:A128290
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%I A128290
%S A128290 1,2,3,4,5,6,7,8,9,22,36,63,109,123,132,158,185,190,199,208,213,231,280,
%T A128290 289,298,307,312,321,333,370,406,458,460,469,485,496,505,518,548,550,
%U A128290 556,559,565,581,584,595,604,640,649,655,667,676,694,703,730,766,802
%N A128290 If p(x) is the product of the digits of the number x and s(x) the sum 
               of the digits then the sequence lists all the numbers n for which 
               p[s(n)]=s[p(n)], with n>=1.
%C A128290 Numbers n such that commutator[s(n),p(n)] = [A007953(n),A007954(n)] = 
               0. - Jonathan Vos Post (jvospost3(AT)gmail.com), May 06 2007
%e A128290 496 -> s(496)=4+9+6=19; p[s(496)]=1*9=9 and p(496)=4*9*6=216; s[p(496)]=2+1+6=9.
%e A128290 845 -> s(845)=8+4+5=17; p[s(845)]=1*7=7 and p(845)=8*4*5=160; s[p(845)]=1+6+0=7.
%p A128290 P:=proc(n) local i,k,w,sp; for i from 1 by 1 to n do w:=0; k:=i; while 
               k>0 do w:=w+k-(trunc(k/10)*10); k:=trunc(k/10); od; k:=w; w:=1; while 
               k>0 do w:=w*(k-(trunc(k/10)*10)); k:=trunc(k/10); od; sp:=w; w:=1; 
               k:=i; while k>0 do w:=w*(k-(trunc(k/10)*10)); k:=trunc(k/10); od; 
               k:=w; w:=0; while k>0 do w:=w+k-(trunc(k/10)*10); k:=trunc(k/10); 
               od; if sp=w then print(i); fi; od; end: P(1000);
%Y A128290 Cf. A007953, A007954.
%Y A128290 Sequence in context: A061013 A037264 A045910 this_sequence A110002 A064158 
               A064702
%Y A128290 Adjacent sequences: A128287 A128288 A128289 this_sequence A128291 A128292 
               A128293
%K A128290 easy,nonn,base
%O A128290 0,2
%A A128290 Paolo P. Lava & Giorgio Balzarotti (ppl(AT)spl.at), May 04 2007

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