Bipartite primes

Computer Science Level 5

Let $p(n)$ denote binary representation of natural number $n$ .For example, $p(7)=111$ .

Let $A(n) = (p(n+p(n))-n)$ for natural number $n$ .

For how many integers between ${3,10000}$ (both inclusive) is $A(n)$ a positive prime number.

The answer is 120.

1 solution

Bill Bell
Mar 1, 2016

from sympy import isprime

def p(n):
    return int(bin(n)[2:])

def A(n):
    return p(n+p(n))-n

count=0
for n in range(3,10001):
    compare=A(n)
    count+=compare>0 and isprime(compare)

print (count)

Bipartite primes

The answer is 120.

1 solution

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