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

Hints
(Greetings from The On-Line Encyclopedia of Integer Sequences!)
A104167 Numbers n which when multiplied by any repunit prime Rp give a Smith number. 0
1540, 1720, 2170, 2440, 5590, 6040, 7930, 8344, 8470, 8920, 23590, 24490, 25228, 29080, 31528, 31780, 33544, 34390, 35380, 39970, 40870, 42490, 42598, 43480, 44380, 45955, 46270, 46810, 46990, 47908, 48790, 49960, 51490, 51625, 52345 (list; graph; refs; listen; history; internal format)
OFFSET

1,1

COMMENTS

Numbers in the sequence must have a digital root of 1

REFERENCES

Oltikar, Sham and Keith Wayland. "Construction of Smith Numbers," Mathematics Magazine, vol. 56(1), 1983, pp. 36-37.

LINKS

S. S. Gupta, Smith Numbers.

EXAMPLE

1720 is a number in the sequence because 1720*Rp is always a Smith number, where Rp is a Repunit prime. Let Rp=11, so 1720*11=18920 which is a Smith number as sum of digits of 18920 is 1+8+9+2+0=20 and sum of digits of prime factors of 18920(i.e. 2*2*2*5*11*43) is also 20 (i.e. 2+2+2+5+1+1+4+3).

CROSSREFS

Cf. A006753, A004022.

Sequence in context: A170793 A202166 A133354 * A200429 A092717 A203134

Adjacent sequences:  A104164 A104165 A104166 * A104168 A104169 A104170

KEYWORD

base,nonn

AUTHOR

Shyam Sunder Gupta (guptass(AT)rediffmail.com), Mar 10 2005

Lookup | Welcome | Wiki | Register | Music | Plot 2 | Demos | Index | Browse | More | WebCam
Contribute new seq. or comment | Format | Transforms | Puzzles | Hot | Classics
Recent Additions | More pages | Superseeker | Maintained by The OEIS Foundation Inc.

Content is available under The OEIS End-User License Agreement .

Last modified February 13 09:25 EST 2012. Contains 205451 sequences.