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Question 2 · Sep 28 · Day 19

Claude on Question 2, Sep 28

Is 9973 a prime number? Think step by step and then answer "[Yes]" or "[No]".

Checking 9973

Since √9973 ≈ 99.9, I only need to test prime divisors up to 99.

Small primes:

  • •2: 9973 is odd → no
  • •3: 9+9+7+3 = 28, not divisible by 3 → no
  • •5: doesn't end in 0 or 5 → no
  • •7: 7 × 1424 = 9968, remainder 5 → no
  • •11: 9−9+7−3 = 4 → no
  • •13: 13 × 767 = 9971, remainder 2 → no
  • •17: 17 × 586 = 9962, remainder 11 → no
  • •19: 19 × 524 = 9956, remainder 17 → no
  • •23: 23 × 433 = 9959, remainder 14 → no
  • •29: 29 × 343 = 9947, remainder 26 → no

Continuing:

  • •31: 31 × 321 = 9951, r 22 → no
  • •37: 37 × 269 = 9953, r 20 → no
  • •41: 41 × 243 = 9963, r 10 → no
  • •43: 43 × 231 = 9933, r 40 → no
  • •47: 47 × 212 = 9964, r 9 → no
  • •53: 53 × 188 = 9964, r 9 → no
  • •59: 59 × 169 = 9971, r 2 → no
  • •61: 61 × 163 = 9943, r 30 → no
  • •67: 67 × 148 = 9916, r 57 → no
  • •71: 71 × 140 = 9940, r 33 → no
  • •73: 73 × 136 = 9928, r 45 → no
  • •79: 79 × 126 = 9954, r 19 → no
  • •83: 83 × 120 = 9960, r 13 → no
  • •89: 89 × 112 = 9968, r 5 → no
  • •97: 97 × 102 = 9894, r 79 → no

No prime ≤ 99 divides 9973, so it has no nontrivial factors. (In fact, 9973 is the largest four-digit prime.)

[Yes]

sha256 0f9f43cf7b4f… · 39 tokens in · 1,357 out · 12.7 s · via Claude Platform on AWS · stopped on its own

Sep 28, the whole dayQuestion 2, every day

Exact recordShowHideThe model id, the run, the verbatim text with line numbers and its full sha256
Model
anthropic/claude-opus-5
pinned anthropic/claude-opus-5-20260723; alias resolved to anthropic/claude-opus-5-20260723 at 2026-09-28 09:00:07 UTC (matches the pin)
Date
2026-09-28 · run 20260928T090007Z-07d4be · scorer v1
Scored
answered · correct · format ok
sha256
0f9f43cf7b4fb0324ab8beba1e867d7f8aef080a647de86f134c5db7f844b2d4
Permalink
https://modeldrift.watch/r/2026-09-28/D2/anthropic/claude-opus-5/
Scored
answered · correct · format ok
Received
2026-09-28 09:00:40 UTC
Run
20260928T090007Z-07d4be
Served by
Claude Platform on AWS · HTTP 200 · finish stop
Size
1,194 characters · 1,357 tokens out incl. hidden reasoning · 12.7 s

Highlighted: the last [Yes]/[No] bracket, which is the scored answer (Yes).

## Checking 9973
Since √9973 ≈ 99.9, I only need to test prime divisors up to 99.
**Small primes:**
- **2:** 9973 is odd → no
- **3:** 9+9+7+3 = 28, not divisible by 3 → no
- **5:** doesn't end in 0 or 5 → no
- **7:** 7 × 1424 = 9968, remainder 5 → no
- **11:** 9−9+7−3 = 4 → no
- **13:** 13 × 767 = 9971, remainder 2 → no
- **17:** 17 × 586 = 9962, remainder 11 → no
- **19:** 19 × 524 = 9956, remainder 17 → no
- **23:** 23 × 433 = 9959, remainder 14 → no
- **29:** 29 × 343 = 9947, remainder 26 → no
**Continuing:**
- **31:** 31 × 321 = 9951, r 22 → no
- **37:** 37 × 269 = 9953, r 20 → no
- **41:** 41 × 243 = 9963, r 10 → no
- **43:** 43 × 231 = 9933, r 40 → no
- **47:** 47 × 212 = 9964, r 9 → no
- **53:** 53 × 188 = 9964, r 9 → no
- **59:** 59 × 169 = 9971, r 2 → no
- **61:** 61 × 163 = 9943, r 30 → no
- **67:** 67 × 148 = 9916, r 57 → no
- **71:** 71 × 140 = 9940, r 33 → no
- **73:** 73 × 136 = 9928, r 45 → no
- **79:** 79 × 126 = 9954, r 19 → no
- **83:** 83 × 120 = 9960, r 13 → no
- **89:** 89 × 112 = 9968, r 5 → no
- **97:** 97 × 102 = 9894, r 79 → no
No prime ≤ 99 divides 9973, so it has no nontrivial factors. (In fact, 9973 is the largest four-digit prime.)
**[Yes]**

End of response · 36 lines · 1,194 characters · sha256 0f9f43cf7b4fb0324ab8beba1e867d7f8aef080a647de86f134c5db7f844b2d4