text: Enneacontagon Number | C program for above approach ; Finding the nth enneacontagon Number ; Driver program to test above function
code: #include <stdio.h> NEW_LINE #include <stdlib.h> NEW_LINE int enneacontagonNum ( int n ) { return ( 88 * n * n - 86 * n ) / 2 ; } int main ( ) { int n = 3 ; printf ( "3rd ▁ enneacontagon ▁ Number ▁ is ▁ = ▁ % d " , enneacontagonNum ( n ) ) ; return 0 ; }