[seqfan] Re: Rant on Maple code
peter.luschny
peter.luschny at googlemail.com
Thu Aug 13 22:36:32 CEST 2009
Searching "futurevalue" results in 110 hits.
I looked at the first page in the order of display.
I did nothing else than to insert the parameters given.
A000217 with(finance): seq(add(futurevalue(k,3,2),k=0..n)/16,n=0..55);
futurevalue(k,3,2)/16 = k.
A000079 with(finance): seq(futurevalue(2,1,n), n=-1..31);
futurevalue(2,1,n) = 2*2^n.
A000225 with(finance):seq(add(futurevalue(1,1,k),k=0..n),n=-1..31);
futurevalue(1,1,k) = 2^k.
A002378 with(finance):seq(add(futurevalue(k,3,2),k=0..n)/8,n=0..50);
futurevalue(k,3,2) = 16k.
A000244 with(finance):seq(futurevalue(3,2,n),n=-1..26);
futurevalue(3,2,n) = 3*3^n.
A001906 with(combinat):with(finance):seq(fibonacci(futurevalue(n,1,1)),n=0..36);
futurevalue(n,1,1) = 2n.
A000330 with(finance):seq(add(futurevalue(k,3,2)*effectiverate(k,1),k=0..n)/16,n=0..44);
futurevalue(k,3,2) = 16k.
A000302 seq(futurevalue(1,3,n),n=0..24);
futurevalue(1,3,n) = 4^n.
A001787 with(finance):seq(add(futurevalue(1,1,n),k=0..n),n=-1..28);
futurevalue(1,3,n) = 4^n.
One more time A001787:
with(finance):seq(add(futurevalue(2,1,n),k=0..n)/2, n=-1..28);
futurevalue(2,1,n) = 2*2^n.
A003462 seq(add(futurevalue(1,2,k),k=0..n),n=-1..25);
futurevalue(1,2,k) = 3^k.
This was page 1. Besides the particular nice
futurevalue(k,3,2)/16 = k
(yes Richard, I learned something, this is giant step
forward to a general method to obfuscate /any/ code)
I thus found the functions
2*2^n, 2^k, 16k, 3*3^n, 2n, 16k, 4^n, 4^n, 2*2^n, 3^k.
----
njas> Joerg suggests removing all the "with(finance)" Maple codes.
njas> I do not agree. Some provide one-line programs
njas> for sequences that would otherwise not have a Maple program.
Number of Maple snippets on this page:
A000217 13, 9 thereof by Lajos
A000079 6, 4 thereof by Lajos
A000225 8, 6 thereof by Lajos
A002378 11, 9 thereof by Lajos
A000244 6, 4 thereof by Lajos
A001906 4, 3 thereof by Lajos
A000330 10, 5 thereof by Lajos
A000302 7, 5 thereof by Lajos
A001787 6, 4 thereof by Lajos
A003462 6, 5 thereof by Lajos
In the case that there are sequences that would otherwise
not have a Maple program this one-liner
FV := (p,i,t) -> p*(1+i)^t;
could be used as a substitute for 'futurevalue'.
njas> In this way we may sometimes find explanations for
njas> sequences that were not known before.
This is a valid policy for the general case. However,
I think it should not be applied in the case under
consideration where this expectation is obviously false.
Cheers Peter
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