

A085445


Numbers equal to exactly twice the sum of the products of each of their digits.


1




OFFSET

1,2


COMMENTS

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.
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


LINKS

Table of n, a(n) for n=1..5.


EXAMPLE

162 = 2*(1*1 + 1*6 + 1*2 + 6*1 + 6*6 + 6*2 + 2*1 + 2*6 + 2*2).


CROSSREFS

Cf. A085444.
Sequence in context: A044763 A165676 A160783 * A048511 A206128 A333101
Adjacent sequences: A085442 A085443 A085444 * A085446 A085447 A085448


KEYWORD

base,fini,full,nonn


AUTHOR

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


STATUS

approved



