Hans Riesel
Encyclopedia
Hans Ivar Riesel is a Swedish
mathematician
who discovered the 18th known Mersenne prime
in 1957, using the computer BESK
. This prime is 23217-1, which consists of 969 digits. He held the record for the largest known prime from 1957 to 1961, when Alexander Hurwitz discovered a larger one. Riesel also discovered the Riesel number
s. After having worked at the Swedish Board for Computing Machinery
, he was awarded his Ph.D.
from Stockholm University
in 1969, and in the same year joined the Royal Institute of Technology
as a senior lecturer and associate professor.
Sweden
Sweden , officially the Kingdom of Sweden , is a Nordic country on the Scandinavian Peninsula in Northern Europe. Sweden borders with Norway and Finland and is connected to Denmark by a bridge-tunnel across the Öresund....
mathematician
Mathematician
A mathematician is a person whose primary area of study is the field of mathematics. Mathematicians are concerned with quantity, structure, space, and change....
who discovered the 18th known Mersenne prime
Mersenne prime
In mathematics, a Mersenne number, named after Marin Mersenne , is a positive integer that is one less than a power of two: M_p=2^p-1.\,...
in 1957, using the computer BESK
BESK
BESK was Sweden's first electronic computer, using vacuum tubes instead of relays. It was developed by Matematikmaskinnämnden and during a short time it was the fastest computer in the world. The computer was completed in 1953 and in use until 1966...
. This prime is 23217-1, which consists of 969 digits. He held the record for the largest known prime from 1957 to 1961, when Alexander Hurwitz discovered a larger one. Riesel also discovered the Riesel number
Riesel number
In mathematics, a Riesel number is an odd natural number k for which the integers of the form k·2n − 1 are composite for all natural numbers n....
s. After having worked at the Swedish Board for Computing Machinery
Swedish Board for Computing Machinery
The Swedish Board for Computing Machinery, Matematikmaskinnämnden , was a Swedish government agency which built Sweden's first computers, BARK and BESK....
, he was awarded his Ph.D.
Ph.D.
A Ph.D. is a Doctor of Philosophy, an academic degree.Ph.D. may also refer to:* Ph.D. , a 1980s British group*Piled Higher and Deeper, a web comic strip*PhD: Phantasy Degree, a Korean comic series* PhD Docbook renderer, an XML renderer...
from Stockholm University
Stockholm University
Stockholm University is a state university in Stockholm, Sweden. It has over 28,000 students at four faculties, making it one of the largest universities in Scandinavia. The institution is also frequently regarded as one of the top 100 universities in the world...
in 1969, and in the same year joined the Royal Institute of Technology
Royal Institute of Technology
The Royal Institute of Technology is a university in Stockholm, Sweden. KTH was founded in 1827 as Sweden's first polytechnic and is one of Scandinavia's largest institutions of higher education in technology. KTH accounts for one-third of Sweden’s technical research and engineering education...
as a senior lecturer and associate professor.