# a+certain+number+of

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**Serial number**— from an identity document A serial number is a unique number assigned for identification which varies from its successor or predecessor by a fixed discrete integer value. Common usage has expanded the term to refer to any unique alphanumeric… …112

**Aleph number**— In the branch of mathematics known as set theory, the aleph numbers are a sequence of numbers used to represent the cardinality (or size) of infinite sets. They are named after the symbol used to denote them, the Hebrew letter aleph (aleph).The… …113

**Pentagonal number theorem**— In mathematics, the pentagonal number theorem, originally due to Euler, relates the product and series representations of the Euler function. It states that:prod {n=1}^infty (1 x^n)=sum {k= infty}^infty( 1)^kx^{k(3k 1)/2}.In other words, :(1 x)(1 …114

**77 (number)**— 77 (seventy seven) is the natural number following 76 and preceding 78. Seventy seven is the smallest positive integer requiring five syllables in English. ← 76 78 → 77 …115

**32 (number)**— ← 31 33 → 32 ← 30 31 32 33 34 35 36 …116

**56 (number)**— ← 55 57 → 56 ← 50 51 52 53 54 55 56 …117

**64 (number)**— ← 63 65 → 64 ← 60 61 62 63 64 65 66 …118

**Tax File Number**— (TFN) is an 8 or 9 digit number issued by the Australian Taxation Office (ATO) to each taxpayer (individual, company, superannuation fund, partnership or trust) to identify their Australian tax dealings. In the past, individuals received a 9… …119

**Random number generator attack**— The security of cryptographic systems depends on some secret data that is known to authorized persons but unknown and unpredictable to others. To achieve this unpredictability, some randomization is typically employed. Modern cryptographic… …120

**Lychrel number**— A Lychrel number is a natural number which cannot form a palindrome through the iterative process of repeatedly reversing its base 10 digits and adding the resulting numbers. This process is called the 196 algorithm . The name Lychrel was coined… …