Prime Number Search

[John Keith]

This is all very interesting, it deserves to be expanded into an article if you feel like doing so. I am particularly interested in seeing the HP 50 programs that you mention.

(07-19-2024 11:57 PM)ttw Wrote:  One generates Stern's Diatomic Series using the two-term recursion: S(n+1)=S(n)+S(n-1)-2*(S(n-1) mod S(n)).

The recurrence in the OEIS page, a(2*n) = a(n), a(2*n+1) = a(n) + a(n+1) is faster to compute because it doesn't require MOD. Here is a program implementing the recurrence. It will run on any RPL calculator, returning the first 2n+1 terms of the sequence.

Code:


\<< \-> n
  \<< 0 1 1 2 n
    FOR k k PICK k PICK DUP ROT + SWAP
    NEXT n 2 * 1 + \->LIST
  \>>
\>>