A triangular number or triangle number counts objects arranged in an equilateral triangle. Triangular numbers are a type of figurate number, other examples...

A centered (or centred) triangular number is a centered figurate number that represents an equilateral triangle with a dot in the center and all its other...

In number theory, the sum of the first n cubes is the square of the nth triangular number. That is, 1 3 + 2 3 + 3 3 + ⋯ + n 3 = ( 1 + 2 + 3 + ⋯ + n ) 2...

mathematics, a square triangular number (or triangular square number) is a number which is both a triangular number and a square number. There are infinitely...

n} th triangular number, then the doubly triangular numbers are the numbers of the form T T n {\displaystyle T_{T_{n}}} . The doubly triangular numbers...

16 Egyptian fraction 1012 = ternary number, (3210) quadruple triangular number (triangular number is 253), number of partitions of 1 into reciprocals...

properties of oblong, triangular, and square numbers: 1 . The number 10 for example, can be arranged as a triangle (see triangular number): But 10 cannot be...

605 = 5 × 112, Harshad number, sum of the nontriangular numbers between the two successive triangular numbers 55 and 66, number of non-isomorphic set-systems...

non-trivial square triangular number. Aside from being the smallest square triangular number other than 1, it is also the only triangular number (other than...

666 is the largest triangular number that is also a repdigit. Since 36 is a triangular number too, 666 is a doubly triangular number. 666 is the sum of...

pronic number, nontotient, Harshad number 703 = 19 × 37, the 37th triangular number, a hexagonal number, smallest number requiring 73 fifth powers for Waring...

A pentagonal number is a figurate number that extends the concept of triangular and square numbers to the pentagon, but, unlike the first two, the patterns...

divides the Euclid number 2999# + 1 3003 – triangular number, only number known to appear eight times in Pascal's triangle; no number is known to appear...

cube numbers and triangular numbers). In the real number system, square numbers are non-negative. A non-negative integer is a square number when its square...

A tetrahedral number, or triangular pyramidal number, is a figurate number that represents a pyramid with a triangular base and three sides, called a tetrahedron...

centered triangular number, happy number 902 = 2 × 11 × 41, sphenic number, nontotient, Harshad number 903 = 3 × 7 × 43, sphenic number, 42nd triangular number...

+ 97 + 101 + 103 + 107 + 109 + 113), nontotient, happy number, sum of 4 consecutive triangular numbers (171 + 190 + 210 + 231) 803 = 11 × 73, sum of three...

406 = 2 × 7 × 29, sphenic number, 28th triangular number, centered nonagonal number, even nontotient, Narayana's cow number HTTP status code for "Not...

number Area code of Cincinnati, Ohio 514 = 2 × 257, it is: a centered triangular number. a nontotient a palindrome in bases 4 (200024), 16 (20216), and 19...

is prime 2015 – Lucas–Carmichael number 2016 – triangular number, number of 5-cubes in a 9-cube, Erdős–Nicolas number, 211-25 2017 – Mertens function zero...

parentheses with a given number of distinct nestings Pascal's triangle, whose entries are the binomial coefficients Triangular arrays of integers in which...

= 7!, superior highly composite number 5041 = 712, centered octagonal number 5050 – triangular number, Kaprekar number, sum of first 100 integers 5051...

A pyramidal number is the number of points in a pyramid with a polygonal base and triangular sides. The term often refers to square pyramidal numbers,...

003 = Smallest 7-digit prime number 1,000,405 = Smallest triangular number with 7 digits and the 1,414th triangular number 1,002,001 = 10012, palindromic...

natural number following 299 and preceding 301. 300 is a composite number and the 24th triangular number. It is also a second hexagonal number. 315 = 32...

19. 19 is the third centered triangular number as well as the third centered hexagonal number. The 19th triangular number is 190, equivalently the sum...

k-gonal number contains k more dots than the previous layer. Each centered k-gonal number in the series is k times the previous triangular number, plus...

the eleventh nontotient (with 50 the fifth). The twelfth triangular number 78 is the only number to have an aliquot sum equal to 90, aside from the square...

this approximation end in 6 and generate a sum of 28 (the seventh triangular number), numbers which represent the first and second perfect numbers, respectively...

003 = smallest 6-digit prime number 100,128 = smallest triangular number with 6 digits and the 447th triangular number 100,151 = twin prime with 100...