I've been away a while, mostly working 60-70 hour weeks.

Found a managers job and the illusion of low-level stability.

Also been exploring elliptic curve cryptography and other fun stuff, like this fun equation...

i = log(n, 2**0.5)
base = (((int((n/(n*(1-(n/((((abs(int(n+(n/(1/((n/(n-i))+(i+1)))))+i)-(i*2))/1))/1/i)))))*i)-i)+i))

...as it relates to A143975 a(n) = floor(n*(n+3)/3)

Most semiprimes n=pq, where p<q, appear to have values k in the sequence, where k is such that n+m mod k equals either p||q or a multiple thereof.

Tested successfully up to 49 bits and counting. Mostly haven't gone further because of work.

Theres a little more math involved, and I've (probably incorrectly) explained the last bit but the gist is the factorization doesn't turn up anything, *however* trial lookups on the sequence and then finding a related mod yields k instead, which can be used to trivially find p and q.

It has some relations to calculating on an elliptic curve but thats mostly over my head, and would probably bore people to sleep.