All about flooble | fun stuff | Get a free chatterbox | Free JavaScript | Avatars    
perplexus dot info

Home > Numbers
Additively Quadratic 2 (Posted on 2023-11-11) Difficulty: 3 of 5
Determine all possible positive integer triplet(s) (F, G, H) such that each of F and G is a prime with F ≤ G, and:

F(F+2) + G(G+2) = H(H+5)

See The Solution Submitted by K Sengupta    
Rating: 5.0000 (1 votes)

Comments: ( Back to comment list | You must be logged in to post comments.)
Some Thoughts The first several without a pattern | Comment 2 of 4 |
I was not able to find a pattern, but here are the solutions limiting primes to under 1,000.

(3,5,5)
(3,19,18)
(7,7,9)
(7,67,66)
(13,19,22)
(13,199,198)
(41,157,161)
(61,547,549)
(67,131,146)
(89,733,737)
(101,607,614)
(103,509,518)
(131,751,761)
(151,691,706)
(163,859,873)
(173,373,410)
(223,709,742)
(229,823,853)
(367,811,889)
(373,839,917)
(467,787,914)
(547,631,834)
(607,727,946)
(607,991,1161)
(751,797,1094)
(787,811,1129)

---------
primes = [i for i in range(1000) if isprime(i)]
size = len(primes)
ans = []

for i in range(size):
    F = primes[i]
    for j in range(i,size):
        G = primes[j]
        LHS = F*(F+2) + G*(G+2)
        H = (-5 + (25 + 4*LHS)**.5)/2
        if H%1 == 0:
            ans.append([F,G,int(H)])

for a in ans:
    print('({},{},{})'.format(a[0],a[1],a[2]))

  Posted by Larry on 2023-11-11 10:03:10
Please log in:
Login:
Password:
Remember me:
Sign up! | Forgot password


Search:
Search body:
Forums (5)
Newest Problems
Random Problem
FAQ | About This Site
Site Statistics
New Comments (7)
Unsolved Problems
Top Rated Problems
This month's top
Most Commented On

Chatterbox:
Copyright © 2002 - 2024 by Animus Pactum Consulting. All rights reserved. Privacy Information