Solution:
The only solution is (a,b,c,p)=(3,1,2,3). First, factor the right hand side. This gives us
2apb=(p+1)((p+2)c−1+(p+2)c−2+⋯+(p+2)+1).
Since gcd(p,p+1)=1 it must be the case that p+1=2x for some positive integer x≤a and so p=2x−1 and p+2=2x+1. Now for x≥3, 2x+1 is not prime if x is odd (since it is 0mod3) and 2x−1 is not prime if x is even (since it is 0mod3). This means x≤2, and the only admissible such x is x=2 since otherwise p is not prime. So, the original equation becomes
2a3b=5c−1.
Now 3∣(5c−1), so evaluating 5c−1 mod 3 gives that c=2d for some positive integer d and hence
2a3b=(5d−1)(5d+1).
Observe 5d−1 and 5d+1 are both even and have greatest common divisor 2 because they are 2 apart. Since 4∣(5d−1) this implies 5d−1=2a−1 and 5d+1=2⋅3b. Now, 3 is not a factor of 5d−1 because 5d−1=2a−1. Thus, by evaluating mod 3, d must be odd. If d>1, this is impossible as 5d−1=(5−1)(5d−1+5d−2+⋯+5+1) and the latter factor has an odd prime factor, contradicting 5d−1 is a power of 2. Thus d=1 and so c=2, implying that 2a3b=24 so a=3 and b=1. Hence, the only solution is (a,b,c,p)=(3,1,2,3).