Re: Repetitive sums of divisors
- To: mathgroup at smc.vnet.net
- Subject: [mg39057] Re: Repetitive sums of divisors
- From: "Allan Hayes" <hay at haystack.demon.co.uk>
- Date: Sun, 26 Jan 2003 05:23:13 -0500 (EST)
- References: <b0tdaa$9fs$1@smc.vnet.net>
- Sender: owner-wri-mathgroup at wolfram.com
"Diana" <diana53xiii at earthlink.remove13.net> wrote in message news:b0tdaa$9fs$1 at smc.vnet.net... > All, > > I know that I can generate the divisors of any integer with the "Divisors" > command. I would like to start with "x" = 10, for example, and generate the > divisors of "x", and then determine the sum of the divisors. I would then > like to increment "x", up to 100, for example. > > Some help with this? Thanks, > > Diana > > Remove 13 on my e-mail address for replies, if desired. > -- > ===================================================== > "God made the integers, all else is the work of man." > L. Kronecker, Jahresber. DMV 2, S. 19. > > Some tools that may be useful: Diana, Plus@@Divisors[#]&/@Range[10,100] {18,12,28,14,24,24,31,18,39,20,42,32,36,24,60,31,42,40,56,30,72,32,63,48,54, \ 48,91,38,60,56,90,42,96,44,84,78,72,48,124,57,93,72,98,54,120,72,120,80,90,6 0,\ 168,62,96,104,127,84,144,68,126,96,144,72,195,74,114,124,140,96,168,80,186,\ 121,126,84,224,108,132,120,180,90,234,112,168,128,144,120,252,98,171,156,217 } Rest[NestWhileList[Plus@@Divisors[1+#]&,9,#<=100&,1, Infinity,-1]] {18,20,32,48,57,90} Allan --------------------- Allan Hayes Mathematica Training and Consulting Leicester UK www.haystack.demon.co.uk hay at haystack.demon.co.uk Voice: +44 (0)116 271 4198 Fax: +44 (0)870 164 0565