|
%I #6 Mar 21 2013 12:59:34
%S 0,50,162,392,648
%N Numbers equal to exactly twice the sum of the products of each of their digits.
%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 n again.
%C Actually, the "sum of the products of the digits" is simply the square of the sum of digits. Sequence is complete. - _Giovanni Resta_, Mar 21 2013
%e 162 = 2*(1*1 + 1*6 + 1*2 + 6*1 + 6*6 + 6*2 + 2*1 + 2*6 + 2*2).
%Y Cf. A085444.
%K base,fini,full,nonn
%O 1,2
%A Chuck Seggelin (barkeep(AT)plastereddragon.com), Jun 30 2003
|
