4*(10^7-1)/9 - (10^6+1)
```run"aprt-cle
Test number  N=? 3444443

Preparatory test
Pass !

3444443 is prime.
0:00:00
OK

Proved prime with 'Ubasic - APRT-CLE.UB'
by Patrick De Geest using a Pentium III 650 MHz chip.
```

4*(10^13-1)/9 - (10^12+1)
```run"aprt-cle
Test number  N=? 4*(10^13-1)\9 - (10^12+1)

Preparatory test
Pass !

Main test  for P= 2
for Q= 3    for Q= 5    for Q= 7    for Q= 13    for Q= 11

Main test  for P= 3
for Q= 7    for Q= 13

Main test  for P= 5
for Q= 11     Pass !

3444444444443 is prime.
0:00:00
OK

Proved prime with 'Ubasic - APRT-CLE.UB'
by Patrick De Geest using a Pentium III 650 MHz chip.
```

4*(10^493-1)/9 - (10^492+1)
```== ID:B286C037F0104 =============================================

PRIMO 1.2.1 - Primality Certificate

-----------------------------------------------------------------
Candidate
-----------------------------------------------------------------
N = 344444444444444444444444444444444444444444444444444444444444\
444444444444444444444444444444444444444444444444444444444444\
444444444444444444444444444444444444444444444444444444444444\
444444444444444444444444444444444444444444444444444444444444\
444444444444444444444444444444444444444444444444444444444444\
444444444444444444444444444444444444444444444444444444444444\
444444444444444444444444444444444444444444444444444444444444\
444444444444444444444444444444444444444444444444444444444444\
4444444444443

Decimal size = 493
Binary size = 1637

Started 01/29/2003 04:17:34 PM
Running time 4mn 49s

Candidate certified prime

=================================================================

Proved prime with 'Primo 1.2.1'
by Patrick De Geest using a Pentium III 650 MHz chip.
```

4*(10^5569-1)/9 - (10^5568+1)
```Xinyao Chen informs me (May 19,2022) that this number is
now a proven palindromic plateau & depression prime.
Proof was done by Maksym Voznyy on May 16, 2016.

See source at
https://stdkmd.net/nrr/records.htm#pdprime
```

4*(10^24757-1)/9 - (10^24756+1)
```3-PRP!
PFGW Version 20041020.Win_Stable (v1.2 RC1c) [FFT v23.8].

```

```

```

( © All rights reserved ) - Last modified : March 15, 2023.

Patrick De Geest - Belgium - Short Bio - Some Pictures
E-mail address : pdg@worldofnumbers.com