Pentagonal numbers

GPTKB entity

Statements (23)
Predicate Object
gptkbp:instanceOf Figurate number
Integer sequence
gptkbp:definedIn P(n) = n(3n-1)/2
gptkbp:differenceBetweenTerms 3n-2
gptkbp:first_terms 1
12
22
35
5
gptkbp:generalizes gptkb:Polygonal_numbers
https://www.w3.org/2000/01/rdf-schema#label Pentagonal numbers
gptkbp:inverseFormula n = (sqrt(24x+1)+1)/6
gptkbp:namedAfter gptkb:Pentagon
gptkbp:OEIS A000326
gptkbp:property Every pentagonal number is a centered nonagonal number
All pentagonal numbers are congruent to 0, 1, or 2 mod 5
gptkbp:recurrence P(n) = P(n-1) + 3n - 2
gptkbp:relatedTo gptkb:Hexagonal_numbers
gptkb:Triangular_numbers
gptkbp:usedIn Partition function
gptkbp:visualizes Dots arranged in pentagon shape
gptkbp:bfsParent gptkb:Polygonal_numbers
gptkbp:bfsLayer 7