login
This site is supported by donations to The OEIS Foundation.

 

Logo


Hints
(Greetings from The On-Line Encyclopedia of Integer Sequences!)
A085445 Numbers equal to exactly twice the sum of the products of each of their digits. 1
0, 50, 162, 392, 648 (list; graph; refs; listen; history; text; internal format)
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 A206121

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

Lookup | Welcome | Wiki | Register | Music | Plot 2 | Demos | Index | Browse | More | WebCam
Contribute new seq. or comment | Format | Style Sheet | Transforms | Superseeker | Recent
The OEIS Community | Maintained by The OEIS Foundation Inc.

License Agreements, Terms of Use, Privacy Policy. .

Last modified November 11 22:31 EST 2019. Contains 329046 sequences. (Running on oeis4.)