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

 

Logo


Hints
(Greetings from The On-Line Encyclopedia of Integer Sequences!)
A287217 Primes p where A196202 reaches a new local minimum, i.e., the value of A196202 is strictly smaller than the value for both the previous prime and the next prime. 0
7, 13, 19, 29, 37, 59, 71, 79, 89, 107, 131, 139, 151, 173, 191, 211, 233, 263, 277, 283, 313, 331, 359, 379, 389, 409, 439, 467, 491, 503, 521, 541, 569, 587, 599, 613, 647, 659, 677, 691, 739, 757, 773, 809, 823, 839, 857, 863, 881, 929, 941, 953, 977, 991 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

COMMENTS

A Wieferich prime p (A001220) is in this sequence iff neither A000040(i-1) nor A000040(i+1) is a Wieferich prime, where i is the index of p in A000040.

Conjecture: There are no consecutive Wieferich primes, i.e., A001220 is a subsequence of this sequence.

The truth of the previous conjecture would follow from the truth of the heuristic assumption that there are about log(log(x)) Wieferich primes below x for large x.

LINKS

Table of n, a(n) for n=1..54.

PROG

(PARI) a196202(n) = lift(Mod(2, n^2)^(n-1))

is(n) = (ispseudoprime(n)) && (a196202(n) < a196202(precprime(n-1))) && (a196202(n) < a196202(nextprime(n+1)))

CROSSREFS

Cf. A000040, A001220, A196202.

Sequence in context: A059647 A059310 A299929 * A101324 A216830 A167462

Adjacent sequences:  A287214 A287215 A287216 * A287218 A287219 A287220

KEYWORD

nonn

AUTHOR

Felix Fröhlich, May 27 2017

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.

License Agreements, Terms of Use, Privacy Policy. .

Last modified July 5 01:22 EDT 2020. Contains 335457 sequences. (Running on oeis4.)