*k*such that all integers of the form

*k*2

^{n}+ 1 (with n taking positive integer values) are composite. In [1], Sierpinski showed that there are infinitely many k with this property. The "Sierpinski problem" asks:

" What is the smallest Sierpinski number ? "It is conjectured that the answer is k = 78557 (the fact that 78557 is a Sierpinski number was discovered in 1962 by John Selfridge).

Waclaw Sierpinski was born on March 14, 1882 in Warsaw.

- Waclaw Sierpinski - from The MacTutor History of Mathematics archive
- Waclaw Sierpinski - from Wikipedia
- The Sierpinski Problem: Definition and Status
- Seventeen or Bust - A Distributed Attack on the Sierpinski Problem

*Sur un problème concernant les nombres k*2

^{n}+ 1."

*Elemente der Mathematik*

**15**, 73-74 (1960).