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%I #10 Apr 16 2018 02:55:17
%S 11,22,33,44,55,66,77,88,99,100,111,122,133,144,155,166,177,188,199,
%T 200,212,224,236,248,300,313,326,339,400,414,428,500,515,600,616,700,
%U 717,800,818,900,919,1000,1010,1020,1030,1040,1050,1060,1070,1080,1090,1100
%N Numbers x which are the concatenation of y and the product of the digits of y.
%e 100 => 1*0 = 0; 326 => 3*2 = 6; 127798 => 1*2*7*7 = 98.
%p P:=proc(n) local k, ok; ok:=0; for k from 1 to ilog10(n) do
%p if convert(convert(trunc(n/10^k), base, 10), `*`)=n mod 10^k then ok:=1; break; fi; od;
%p if ok=1 then if n<100 or k<ilog10(n) then n; fi; fi; end: seq(P(i), i=1..1100);
%o (PARI) isok(n) = {d = digits(n); for (k=1, #d-1, da = vector(k, i, d[i]); db = vector(#d-k, i, d[k+i]); na = fromdigits(da); nb = fromdigits(db); if ((nb && db[1] != 0) || (nb==0), if (prod(j=1, k, da[j]) == nb, return (1));););} \\ _Michel Marcus_, Apr 13 2018
%Y Cf. A007954, A108203.
%K nonn,base,easy
%O 1,1
%A _Paolo P. Lava_, Apr 10 2018
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