[TI-83] Various Number Theory Things

[rabbit]

TI-83 lacks a few things helpful for Number Theory, so I added them in during a free today, thought they may be helpful to others:

prgmMODULUS
Used to find even divisibility (VERY HELPFUL!).  This is a requirement for other programs below.

Code Select Expand

:If F:Then
:E/F->G
:F*(G-int(G))->G
:If G<0:G+F->G
:Else
:0->G
:End
Result: 0 F divides E evenly (ie: F = 2, E = 10).
remainder otherwise.

prgmSUMFACTS
Sums all factors (divisors) of a given number, 1 and the number inclusive.  Useful in finding k-perfect numbers.

Code Select Expand

:Input "NUM=",A
:0->K
:For(I,1,A+1)
:A->E
:I->F
:prgmMODULUS
:If G=0
:K+I->K
:End
:Disp K

prgmFACTOR
Displays all factors of a number, 1 and number exclusive

Code Select Expand

:Input "NUM=",A
:0->K
:For(I,1,A+1)
:A->E
:I->F
:prgmMODULUS
:If G=0
:Disp I
:End

prgmPF
Launcher for prgmPRMEFACT

Code Select Expand

:ClrHome
:Input "NUM=",A
:prgmPRMEFACT

prgmPRMEFACT
Displays the prime factorization (kind of) of a number

Code Select Expand

:2->I
:While I<A
:A->E
:I->F
:prgmMODULUS
:If G=0:Then
:Disp I
:A/I->A
:Else
:I+1->I
:End
:End
:Disp A

[deadly7]

Neat.  I like the last one the most.

Why are you using an 83?  They're terrible calculators.

[Sidoh]

Neat.  I like the last one the most.

Why are you using an 83?  They're terrible calculators.

...

Nice, rabbit.  I doubt I'll ever have much use to do number theory on a graphing calculator (with the stuff I've done, I've used my computer), but I'll keep them in mind. :P

[rabbit]

Neat.  I like the last one the most.

Why are you using an 83?  They're terrible calculators.

We haven't been allowed 83's in NT, we've been using TI-06's all year (the blue ones for like, 3rd graders), but even those have a mod button (INT/) :\

[Joe]

I don't have my TI-83 handy at the moment (it's at school) but I could have sworn there was a mod function in the catalog.

[MyndFyre]

I got to use an 89 in college calc.  :D

[rabbit]

Yeah.  Sang (a Korean, no doubt!) has an 89 and is in our class.  The 89 is what inspired me..

[Nate]

My friend has an 89...so cheap

[deadly7]

I have an 86 and I can use my brother's 89 whenever I want. :D!