pentagonal? ( n -- ? )


Vocabulary
project-euler.common

Inputs
nan object


Outputs
?an object


Definition
USING: kernel math math.functions ;

IN: project-euler.common

: pentagonal? ( n -- ? )
dup 0 > [ 24 * 1 + sqrt 1 + 6 / 1 mod zero? ] [ drop f ] if
; inline