User:Hermann Stamm-Wilbrandt

I did study computer science with 2nd subject mathematics at university of Dortmund 1985-1990. From 1990-1995 I was researcher at computer science department of university of Bonn. My 1992 paper "Evaluating production systems with delete operator is PSPACE-complete" with H. Kleine Büning gives me an Erdös number 4. In 1995 I joined IBM Scientific Center at Heidelberg. In 2000 I was co-author of Journal of Computational Physics paper "Record Breaking Optimization Results Using the Ruin and Recreate Principle", working in IBM Optimization department Heidelberg/Germany.

I always was and still am interested in number theory.

5/8/2025 was my last workday of early retirement at age of 60, after working 30 years at IBM. More on studying Mathematics, challenging the "s" in https and the 150,000 USD EFF prime number award here:

https://stamm-wilbrandt.de/en/#future

Since 10/2025 I am student of Mathematics at Heidelberg University:

https://stamm-wilbrandt.de/GraphvizFiddle/#_math

Started contributing to oeis back in 2014.

My new sequences:

• 03/2026: A393389 „Euclid-Carmichael numbers: Carmichael numbers 1 + product of "powers of" first n primes.”

• 01/2026: A392688 is on Jacobson constant with maximal Hardy-Littlewood value for x^2+x+A.

• 01/2026: A392244 "Number of primes of the form b^2 + (b+1)^2 for b <= 10^n."

a(11) computation (gist) took 5.8h real time and 1110.5h cpu time (46.3 days) on 192C/384T 8-socket server. https://gist.github.com/Hermann-SW/fe69d723ddc2b8b6ff7666b747aad1aa

• 11/2025: A391020 "Numbers k such that no numbers of the form 1 + (product of k distinct primes of first k+1 primes) are prime."

Added characterizations to A012132 [composites of the form b^2 + (b+1)^2] in 2014 and 01/2026.

Computation of prime count x≤10¹¹ for x^2 + x + A (with Jacobson and Williams A = 3399714628553118047) took 27:10h real time / 215.55 days cpu time in 01/2026:

https://gist.github.com/Hermann-SW/14c7c7c6acd1f69f8dc36e51af1fdb3a

Added a(11) to A331876 (Euler polynomial prime count k≤10¹¹), 15:42h real time / 129.6 days cpu time in 01/2026.

"6(4) interlaced bisections" SVGs, added to sequences affected (eg. A049651(A006451)) in 2019(2014).

6(4) sequences identified by analyzing connected components of big "oeis share bisection" graph(manually):

ASCII animation for generalized binomial formula (left), added to A007318 in 2015:

Infinite sum of center binomial reciprocals is 3/2 (right), added to A144394 in 2014.