Palindromic prime

In mathematics, a palindromic prime is a prime number that is also a palindromic number. Palindromicity depends on the base of the number system and its notational conventions, while primality is independent of such concerns. The first few decimal palindromic primes are:2, 3, 5, 7, 11, 101, 131, 151, 181, 191, 313, 353, 373, 383, 727, 757, 787, 797, 919, 929, …

Higgs prime

A Higgs prime, named after Denis Higgs, is a prime number with a totient that evenly divides the square of the product of the smaller Higgs primes. To put it algebraically, given an exponent a, a Higgs prime Hpn

Fortunate number

A Fortunate number, named after Reo Fortune, is the smallest integer m > 1 such that, for a given positive integer n, pn# + m is a prime number, where the primorial pn# is the product of the first n prime numbers

Alternating factorial

In mathematics, an alternating factorial is the absolute value of the alternating sum of the first n factorials of positive integers

Stern prime

A Stern prime, named for Moritz Abraham Stern, is a prime number that is not the sum of a smaller prime and twice the square of a non zero integer. That is, if for a prime q there is no smaller prime p and nonzero integer b such that q = p + 2b2, then

Centered octagonal number

A centered octagonal number is a centered figurate number that represents an octagon with a dot in the center and all other dots surrounding the center dot in successive octagonal layers. The centered octagonal numbers are the same as the odd square

Centered decagonal number

A centered decagonal number is a centered figurate number that represents a decagon with a dot in the center and all other dots surrounding the center dot in successive decagonal layers. The centered decagonal number for n is given by the

Highly cototient number

In number theory, a branch of mathematics, a highly cototient number is a positive integer which is above 1 and has more solutions to the

Centered heptagonal number

A centered heptagonal number is a centered figurate number that represents a heptagon with a dot in the center and all other dots surrounding the center dot in successive heptagonal layers. The centered heptagonal number for n is given by the formula

Gregory number

In mathematics, a Gregory number, named after James Gregory, is a real number of the form

4 Park Avenue

4 Park Avenue is a 22-story building in the Murray Hill neighborhood of Manhattan in New York City. Designed by Warren and Wetmore, the structure was built for Alfred Gwynne Vanderbilt and opened in 1912 as a hotel. It is along the west side of Park