The OEIS is supported by the many generous donors to the OEIS Foundation.

 Hints (Greetings from The On-Line Encyclopedia of Integer Sequences!)
 A355601 a(1) = 47. For n > 1, a(n) = smallest prime q such that q^(a(n-1)-1) == 1 (mod a(n-1)^2). 5
 47, 53, 521, 6037, 3347, 4931, 105667, 1131259, 4739509, 175166071, 3834885547 (list; graph; refs; listen; history; text; internal format)
 OFFSET 1,1 COMMENTS Is this overall an increasing sequence or does it enter a cycle? The sequence decreases for the first time at n = 5. LINKS Table of n, a(n) for n=1..11. MATHEMATICA nxt[a_]:=Module[{q=3}, While[PowerMod[q, a-1, a^2]!=1, q=NextPrime[q]]; q]; NestList[ nxt, 47, 10] (* The program will take a long time to run. *) (* Harvey P. Dale, Jan 31 2023 *) PROG (PARI) seq(start, terms) = my(x=start, i=1); print1(start, ", "); while(1, forprime(q=1, , if(Mod(q, x^2)^(x-1)==1, print1(q, ", "); x=q; i++; if(i >= terms, break({2}), break)))) seq(47, 20) \\ Print initial 20 terms of sequence CROSSREFS Row n = 15 of A249162. Cf. A355597, A355598, A355599, A355600, A355602. Sequence in context: A155139 A106279 A275022 * A048581 A169716 A045140 Adjacent sequences: A355598 A355599 A355600 * A355602 A355603 A355604 KEYWORD nonn,hard,more AUTHOR Felix Fröhlich, Jul 09 2022 STATUS approved

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

Last modified July 25 03:25 EDT 2024. Contains 374586 sequences. (Running on oeis4.)