triangular number
Bowling pin count
A triangular number is an integer that can be represented as a triangle of dots: 1, 3, 6, 10, 15, and so on.
Each triangular number equals the sum of consecutive integers starting from 1: the fifth triangular number is 1+2+3+4+5=15.
The name comes from arranging that many objects into an equilateral triangle pattern.
Number theory pioneer
- polygonalHaving many straight sides
- binomialExpression with two terms
- combinatoricsMathematics of discrete enumeration
- PascalFrench male name
formula · theorem · proof · consecutive · summation · integer · natural numbers · arithmetic
Pisan mathematician, numeral importer
- tetrahedralHaving four triangular sides
- pentagonalHaving five angles
- hexagonalSix-edged polygon's form
- oblongElongated in one direction
pyramidal · pattern · progression · series · recurrence · generating function · index · rank
Small circular marks
- arrayOrdered collection or display
- arrangementOrdered configuration or agreement
- equilateralHaving all sides congruent
- rowsSide-by-side sequences
stacking · bowling pins · diagonal · lattice · grid · visual · diagram · vertices
Combinations of two
- combinationsUnions of separate parts
- tournamentMulti-round competitive event
- round-robinFormat ensuring universal matchups
- connectionsRelationships between things
network · binomial coefficient · choose · counting · matching · scheduling
Gauss
Number theory pioneer
- polygonalHaving many straight sides
- binomialExpression with two terms
- combinatoricsMathematics of discrete enumeration
Pascal · formula · theorem · proof · consecutive · summation · integer · natural numbers · arithmetic · algebraic
Fibonacci
Pisan mathematician, numeral importer
- tetrahedralHaving four triangular sides
- pentagonalHaving five angles
- hexagonalSix-edged polygon's form
oblong · pyramidal · pattern · progression · series · recurrence · generating function · index · rank · position
dots
Small circular marks
- arrayOrdered collection or display
- arrangementOrdered configuration or agreement
- equilateralHaving all sides congruent
rows · stacking · bowling pins · diagonal · lattice · grid · visual · diagram · vertices · tessellation
pairings
Combinations of two
- combinationsUnions of separate parts
- tournamentMulti-round competitive event
- round-robinFormat ensuring universal matchups
connections · network · binomial coefficient · choose · counting · matching · scheduling
triangular numberprime number
Integer with two divisors
composite number · perfect square · factorial · Fibonacci number · power of two
number, triangle, triangles, numeral, triangular, enumerate, trigonometry, trigonometric