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  1. #include <stdio.h>
  2. //a{n} = 2a{n-1} + a{n-2}, a{1}=2, a{2}=3(再帰なし版)
  3.  
  4. int main(void) {
  5.     int n = 4;
  6.     int a, b = 3, c = 2; 
  7.     for(int i = 3; i <= n; i++){
  8.         a = 2*b + c;
  9.        c = b;
  10.         b = a;
  11.  
  12.     }
  13.     printf("数列a%dの値は%d\n", n, a);
  14. 	return 0;
  15. }
  16.  
  17.  
Success #stdin #stdout 0s 5292KB
comments (?)
stdin 
Standard input is empty
stdout 
数列a4の値は19
https://ideone.com/OYu319
language:
C (gcc 8.3)
created:
72 days ago
visibility:
public

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