cp's OEIS Frontend

A281745 Numbers k with the property that the square root of the product of the digits of k is equal to the sum of the square roots of its digits.

%I A281745 #31 Aug 14 2017 03:25:26
%S A281745 1,2,3,4,5,6,7,8,9,44,149,194,228,282,333,419,491,822,914,941,11199,
%T A281745 11444,11919,11991,14144,14414,14441,19119,19191,19911,41144,41414,
%U A281745 41441,44114,44141,44411,91119,91191,91911,99111,11111449,11111494,11111944,11114149
%N A281745 Numbers k with the property that the square root of the product of the digits of k is equal to the sum of the square roots of its digits.
%H A281745 Chai Wah Wu, <a href="/A281745/b281745.txt">Table of n, a(n) for n = 1..10000</a>
%e A281745     1 is a term because     sqrt(1) = sqrt(1);
%e A281745    44 is a term because   sqrt(4*4) = sqrt(4) + sqrt(4);
%e A281745   941 is a term because sqrt(9*4*1) = sqrt(9) + sqrt(4) + sqrt(1).
%t A281745 Select[Range[10^6], Sqrt[Times @@ #] == Total[Sqrt@ #] &@ IntegerDigits@ # &] (* _Michael De Vlieger_, Feb 02 2017 *)
%o A281745 (PARI) isok(n) = my(d = vecsort(digits(n))); sqrt(prod(k=1, #d, d[k])) == sum(k=1, #d, sqrt(d[k])); \\ _Michel Marcus_, Jan 29 2017
%Y A281745 Cf. A007953, A007954, A034710.
%K A281745 nonn,base
%O A281745 1,2
%A A281745 _José de Jesús Camacho Medina_, Jan 28 2017
%E A281745 More terms from _Jon E. Schoenfield_, Jan 30 2017