gpt pro 5.4 attempt on Math-790
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Contents
Problem #383 (Round 2)
1) ROUND-2 OBJECTIVE
Path A (proof-oriented constructive progress). Round 1 had examples through $k=6$ and no example for $k=7$ in the search range used there. The new aim is to push the exact search further and replace "none found" by explicit rigorous constructions for larger $k$.
2) Round-1 FOUNDATION USED
I use the Round-1 reformulation:
for a prime $p>k$, \[ P\!\left(\prod_{i=0}^{k}(p^2+i)\right)=p \] is equivalent to \[ P(p^2+i)\le p\qquad (1\le i\le k). \]
So it is enough to exhibit primes $p$ such that each of the integers \[ p^2+1,\dots,p^2+k \] is $p$-smooth.
3) NEW INSIGHT / TOOL (ROUND-2)
The new ingredient is not a new theorem but a new exact computational certificate: I found and verified explicit primes for \[ k=7,\ 8,\ 9. \] This strictly advances Round 1, which only had examples through $k=6$.
4) ATTACK PLAN (ROUND-2)
The exact Round-1 gap was the absence of any example for $k=7$ in the earlier search range. The new plan is:
- search much farther than Round 1;
- for each successful prime $p$, give exact factorisations of $p^2+i$ for all $1\le i\le k$;
- conclude rigorously that the largest prime factor of the whole product is exactly $p$.
5) WORK (ROUND-2)
Example for $k=7$.
Take \[ p=510569. \] Then the exact factorisations are:- $p^2+1=2\cdot 37\cdot 31721\cdot 111053$;
- $p^2+2=3\cdot 2731\cdot 4651\cdot 6841$;
- $p^2+3=2^2\cdot 13\cdot 43\cdot 523\cdot 222913$;
- $p^2+4=5\cdot 17\cdot 29^2\cdot 641\cdot 5689$;
- $p^2+5=2\cdot 3\cdot 7\cdot 23\cdot 167\cdot 1061\cdot 1523$;
- $p^2+6=11\cdot 59\cdot 101\cdot 991\cdot 4013$;
- $p^2+7=2^3\cdot 71\cdot 401\cdot 449\cdot 2549$.
Every prime shown is $<p$. Since $p>7$, none of $p^2+1,\dots,p^2+7$ is divisible by $p$. Therefore the factor $p^2$ contributes the only copies of $p$ to \[ \prod_{i=0}^{7}(p^2+i), \] and all other prime divisors are $<p$. Hence \[ P\!\left(\prod_{i=0}^{7}(p^2+i)\right)=p. \]
Example for $k=8$.
Take \[ p=2869123. \] Then:- $p^2+1=2\cdot 5\cdot 489337\cdot 1682249$;
- $p^2+2=3^6\cdot 82129\cdot 137491$;
- $p^2+3=2^2\cdot 7\cdot 31\cdot 5449\cdot 1740451$;
- $p^2+4=13\cdot 251969\cdot 2513089$;
- $p^2+5=2\cdot 3\cdot 43\cdot 563\cdot 1321\cdot 42901$;
- $p^2+6=5\cdot 11^2\cdot 149\cdot 313\cdot 291751$;
- $p^2+7=2^4\cdot 701\cdot 9473\cdot 77477$;
- $p^2+8=3\cdot 953\cdot 4003\cdot 719281$.
Again every displayed prime is $<p$, and $p>8$ implies $p$ does not divide $p^2+i$ for $1\le i\le 8$. Therefore \[ P\!\left(\prod_{i=0}^{8}(p^2+i)\right)=p. \]
Example for $k=9$.
Take \[ p=3092701. \] Then:- $p^2+1=2\cdot 1373\cdot 7237\cdot 481301$;
- $p^2+2=3^2\cdot 17\cdot 41\cdot 89\cdot 1289\cdot 13291$;
- $p^2+3=2^2\cdot 73\cdot 104947\cdot 312121$;
- $p^2+4=5\cdot 101\cdot 137\cdot 1553\cdot 89021$;
- $p^2+5=2\cdot 3\cdot 7^2\cdot 30781\cdot 1056929$;
- $p^2+6=11\cdot 1709\cdot 5021\cdot 101333$;
- $p^2+7=2^4\cdot 919\cdot 2417\cdot 269131$;
- $p^2+8=3\cdot 641\cdot 5939\cdot 837497$;
- $p^2+9=2\cdot 5\cdot 37\cdot 15313\cdot 1688161$.
All displayed prime divisors are $<p$, and $p>9$ implies $p$ does not divide $p^2+i$ for $1\le i\le 9$. Hence \[ P\!\left(\prod_{i=0}^{9}(p^2+i)\right)=p. \]
Consequences for Problem #382.
Each of the three examples above also gives a bad interval: \[ [p^2,p^2+7],\qquad [p^2,p^2+8],\qquad [p^2,p^2+9]. \] So the Problem #383 search now yields rigorous constructions for bad intervals of lengths $7,8,9$.6) ADVERSARIAL VERIFICATION
I checked the key logical points.
- Could one of the numbers $p^2+i$ be divisible by $p$? No, because $1\le i\le k<p$ in all three examples, so $p$ does not divide $p^2+i$.
- Is it enough to factor only $p^2+1,\dots,p^2+k$? Yes. The factor $p^2$ already contributes the prime $p$, and once all other factors are shown to have prime divisors $<p$, the largest prime divisor of the full product is exactly $p$.
- Could there be a larger hidden prime factor in one of the listed numbers? No. The displayed decompositions are exact factorisations.
7) FINAL
UNRESOLVED (BUT STRICTLY ADVANCED).
Round 2 replaces the Round-1 frontier \[ k\le 6 \] by the rigorously verified frontier \[ k\le 9, \] through explicit primes for \[ k=7,\ 8,\ 9. \]
This is substantial constructive progress toward the conjecture, but it does not prove that for every fixed $k$ there are infinitely many such primes.
8) COMPLETION ESTIMATE
COMPLETION: 35%
9) REFERENCES
- T. F. Bloom, Erdős Problem #383, accessed 2026-03-08,
https://www.erdosproblems.com/383.