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A085446 Numbers divisible by twice the sum of the products of each of their digits, excluding even multiples of 10. 2

%I #7 Sep 24 2017 06:09:44

%S 162,324,392,512,648,1134,1296,1944,2106,2592,2704,3402,4212,4536,

%T 5022,5184,5632,5832,7128,7514,7744,8424,8748,9072,10044,10206,10368,

%U 10406,11016,11502,11664,12032,12312,12716,13122,13608,14256,14504,14904

%N Numbers divisible by twice the sum of the products of each of their digits, excluding even multiples of 10.

%C Take a number n, create a table with d columns and rows where d=number of digits of n. Each column corresponds to a digit of n and each row to a digit of n. In each cell, multiply the two digits of n represented by that row and column. Add up the sums of all of the rows and all of the columns to get a new number m which divides n.

%H Harvey P. Dale, <a href="/A085446/b085446.txt">Table of n, a(n) for n = 0..1000</a>

%e 512 / (2*(5*5 + 5*1 + 5*2 + 1*5 + 1*1 + 1*2 + 2*5 + 2*1 + 2*2)) = 4.

%t Select[Range[15000],!Divisible[#,10]&&Divisible[#,2Total[Times @@@ Tuples[ IntegerDigits[#],2]]]&] (* _Harvey P. Dale_, Aug 19 2014 *)

%Y Cf. A085444.

%K base,nonn

%O 0,1

%A Chuck Seggelin (barkeep(AT)plastereddragon.com), Jun 30 2003

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Last modified August 9 01:19 EDT 2024. Contains 375024 sequences. (Running on oeis4.)