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Search: id:A085444
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| A085444 |
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Numbers evenly divisible by twice the sum of the products of each of their digits. |
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+0
3
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| 10, 50, 100, 162, 200, 324, 392, 500, 512, 648, 810, 1000, 1120, 1134, 1296, 1400, 1620, 1944, 2000, 2106, 2300, 2430, 2592, 2704, 2800, 3200, 3240, 3402, 3920, 4000, 4050, 4100, 4212, 4536, 4600, 5000, 5022, 5120, 5184, 5632, 5832, 6050, 6400, 6480
(list; graph; listen)
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OFFSET
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0,1
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COMMENT
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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 evenly into n.
"The sum of the products of each of [the] digits" is just the square of the sum of the digits. - Frank Adams-Watters (FrankTAW(AT)Netscape.net), Jul 17 2006
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EXAMPLE
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512 / 2*((5*5)+(5*1)+(5*2)+(1*5)+(1*1)+(1*2)+(2*5)+(2*1)+(2*2)) = 4
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CROSSREFS
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Cf. A085445, A085446.
Sequence in context: A051947 A061861 A036786 this_sequence A102915 A153780 A008531
Adjacent sequences: A085441 A085442 A085443 this_sequence A085445 A085446 A085447
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KEYWORD
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base,nonn
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AUTHOR
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Chuck Seggelin (barkeep(AT)plastereddragon.com), Jun 30 2003
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