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The Ulam spiral or prime spiral is a graphical depiction of the set of prime numbers, devised by mathematician Stanisław Ulam in 1963 and popularized in Martin Gardner's Mathematical Games column in Scientific American a short time later. [1] It is constructed by writing the positive integers in a square spiral and specially marking the prime ...
The following table compares general and technical information for a selection of common and uncommon Texas Instruments graphing calculators. Many of the calculators in this list have region-specific models that are not individually listed here, such as the TI-84 Plus CE-T, a TI-84 Plus CE designed for non-French European markets.
The proof of Primecoin's operation takes the form of chains of prime numbers. [13] [14] [15] Finding the first number of the chain becomes exponentially more difficult as the length of the chain increases. Checking the reasonable size of chains of prime numbers can be efficiently performed by all nodes in the network.
The tube technology of the ANITA was superseded in June 1963 by the U.S. manufactured Friden EC-130, which had an all-transistor design, a stack of four 13-digit numbers displayed on a 5-inch (13 cm) cathode-ray tube (CRT), and introduced Reverse Polish Notation (RPN) to the calculator market for a price of $2200, which was about three times ...
The Fuller calculator, sometimes called Fuller's cylindrical slide rule, is a cylindrical slide rule with a helical main scale taking 50 turns around the cylinder. This creates an instrument of considerable precision – it is equivalent to a traditional slide rule 25.40 metres (1,000 inches) long.
A Belphegor number is a palindromic number in the form of () ().The sequence of the first four Belphegor numbers is: ,,,, … Dubner noticed that 16661 is a prime number. By adding zeroes directly on both sides of the 666, Dubner found more palindromic prime numbers, including the Belphegor prime, which is second in the sequence.
All Mersenne primes are of the form M p = 2 p − 1, where p is a prime number itself. The smallest Mersenne prime in this table is 2 1398269 − 1. The first column is the rank of the Mersenne prime in the (ordered) sequence of all Mersenne primes; [33] GIMPS has found all known Mersenne primes beginning with the 35th. #
Sumlock-Anita Electronics also assembled in Britain some of the Rockwell hand-held calculators, including Rockwell models 8R, 10R, 18R, 20R, 21R, 30R, 31R. The "Panaplex" is a gas-discharge display, using 7 segments to represent each number, within a thin glass "sandwich". The numerals glow amber. This list of calculator models may not be complete.