A354677 a(n) = number of near-Wieferich primes with |A| <= 1000 less than 10^n.

3, 24, 167, 698, 1155, 1502, 1812, 2064, 2297

Offset: 1

Author

Felix Fröhlich, Jun 02 2022

Keywords

• nonn
• hard
• more

Comments

n | a(n) | A006880(n) | a(n)/A006880(n)*100

--------------------------------------------

1 | 3 | 4 | 75.000000

2 | 24 | 25 | 96.000000

3 | 167 | 168 | 99.404761

4 | 698 | 1229 | 56.794141

5 | 1155 | 9592 | 12.041284

6 | 1502 | 78498 | 1.913424

7 | 1812 | 664579 | 0.272653

8 | 2064 | 5761455 | 0.035824

9 | 2297 | 50847534 | 0.004517

Crossrefs

Cf. A006880, A195988, A246568, A258367, A353141, A354675, A354676, A354678.

Programs

PARI

a258367(n) = abs(centerlift(Mod(2, n^2)^((n-1)/2))\/n) \\ after Charles R Greathouse IV in A258367
my(i=0, x=10); forprime(p=3, , if(p > x, print1(i, ", "); x=10*x); if(a258367(p) <= 1000, i++))