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!)
A082475 Prime index i for consecutive primes p(i),p(i+1),p(i+2),p(i+3) that do not have a solution for the congruences p(i)^x+p(i+1)^x = p(i+2) mod p(i+3) and p(i+1)^x-p(i)^x = p(i+2) mod p(i+3). 1
2, 16, 20, 25, 29, 31, 33, 35, 36, 41, 45, 52, 62, 64, 79, 81, 83, 85, 88, 91, 96, 102, 103, 110, 114, 116, 117, 119, 122, 136, 154, 155, 164, 167, 172, 173, 183, 185, 188, 190, 211, 218, 219, 220, 225, 229, 232, 233, 234, 238, 246, 249, 252, 256, 262, 276, 277 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

LINKS

Table of n, a(n) for n=1..57.

EXAMPLE

For primes 3,5,7,11:

3^x+5^x = 7 mod 11 has no solutions.

5^x-3^x = 7 mod 11 has no solutions.

PROG

(PARI) list_A082475(lim)={my(f, p0=2, p1=3, p2=5, p3=7); for(p=1, lim, f=0; for(x=0, p3-1, if((p0^x + p1^x)%p3 == p2 || (p1^x-p0^x)%p3 == p2, f=1; break)); if(f==0, print1(p", ")); p0=p1; p1=p2; p2=p3; p3=prime(p+4))};

CROSSREFS

Cf. A082371.

Sequence in context: A161802 A323193 A050850 * A333998 A081767 A093026

Adjacent sequences:  A082472 A082473 A082474 * A082476 A082477 A082478

KEYWORD

nonn

AUTHOR

Cino Hilliard, May 11 2003

EXTENSIONS

Corrected sequence and program Charles R Greathouse IV, Oct 09 2009

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 September 22 11:06 EDT 2020. Contains 337289 sequences. (Running on oeis4.)