Timeline for How to define a function that satifies this condition?

9 events

when toggle format	what		by	license	comment
Apr 19 at 5:39	vote	accept	Teflon
Apr 19 at 0:54	history	edited	Bill Dubuque		edited tags
Apr 18 at 17:31	vote	accept	Teflon
Apr 18 at 17:36
Apr 18 at 17:24	answer	added	Greg Martin		timeline score: 1
Apr 18 at 17:11	history	edited	Greg Martin	CC BY-SA 4.0	deleted 2 characters in body
Apr 18 at 17:10	comment	added	JMoravitz		In the end though, I would personally find it easiest to build this by defining a piecewise defined function, and define each part separately based on the ones-digit of $n$. The overall function will then follow $f(n) = f(n-10)+30$ and so could be written in terms of $n - (n\%10)$ coupled with this piecewise function.
Apr 18 at 17:10	comment	added	freakish		Are you asking about partial sums of some sequence? Either way, if you know how to define it programmatically then you know how to define it mathematically. The same definition works, algorithms are completely valid mathematical definitions.
Apr 18 at 17:08	comment	added	JMoravitz		There are multiple ways you could do this... especially if you allow if-conditions in the middle of your expression. Consider using %10 to find the ones-digit of $n$, an if-condition (or disguised if-condition) to determine if the ones-digit was zero, multiplication as necessary, and floor functions if you want to have certain values repeat in the calculation.
Apr 18 at 17:00	history	asked	Teflon	CC BY-SA 4.0