The OEIS Foundation is supported by donations from users of the OEIS and by a grant from the Simons Foundation.

 Hints (Greetings from The On-Line Encyclopedia of Integer Sequences!)
 A255922 Bases b for which exactly one Wieferich prime p with p < b exists such that p is a base-b Wieferich prime. 11
 5, 7, 8, 9, 10, 13, 21, 22, 23, 24, 25, 27, 29, 30, 31, 32, 33, 35, 38, 42, 43, 44, 45, 46, 48, 50, 54, 55, 60, 61, 64, 70, 74, 77, 78, 79, 85, 91, 94, 98, 100, 105, 110, 112, 113, 115, 120, 122, 126, 128, 131, 132, 133, 136, 138, 141, 150, 151, 152, 153, 154 (list; graph; refs; listen; history; text; internal format)
 OFFSET 1,1 COMMENTS Numbers b such that A255920(n) = 1. LINKS Felix Fröhlich, Table of n, a(n) for n = 1..10000 PROG (PARI) is(n) = my(i=0); forprime(p=1, n-1, if(Mod(n, p^2)^(p-1)==1, i++); if(i > 1, return(0))); i==1 CROSSREFS Cf. A255920. Cf. bases b with exactly k base-b Wieferich primes less than b: A255921 (k=0), A255923 (k=2), A255924 (k=3), A255925 (k=4), A325881 (k=5), A325882 (k=6), A325883 (k=7), A325884 (k=8), A325885 (k=9), A325886 (k=10). Sequence in context: A261917 A111339 A273786 * A241028 A171097 A166460 Adjacent sequences:  A255919 A255920 A255921 * A255923 A255924 A255925 KEYWORD nonn AUTHOR Felix Fröhlich, Mar 12 2015 STATUS approved

Lookup | Welcome | Wiki | Register | Music | Plot 2 | Demos | Index | Browse | More | WebCam
Contribute new seq. or comment | Format | Style Sheet | Transforms | Superseeker | Recent
The OEIS Community | Maintained by The OEIS Foundation Inc.

Last modified September 27 09:09 EDT 2020. Contains 337380 sequences. (Running on oeis4.)