The OEIS mourns the passing of Jim Simons and is grateful to the Simons Foundation for its support of research in many branches of science, including the OEIS.
The OEIS is supported by the many generous donors to the OEIS Foundation.

 Hints (Greetings from The On-Line Encyclopedia of Integer Sequences!)
 A294722 Numbers k such that (44^k - 1)/43 is prime. 1
 5, 31, 167, 100511 (list; graph; refs; listen; history; text; internal format)
 OFFSET 1,1 COMMENTS The number corresponding to a(4) is a probable prime. These are the indices of base-44 repunit primes, i.e., numbers k such that A002275(k) interpreted as a base-44 number and converted to decimal is prime. - Felix Fröhlich, Nov 08 2017 LINKS Table of n, a(n) for n=1..4. P. Bourdelais, A generalized repunit conjecture MATHEMATICA ParallelMap[ If[ PrimeQ[(44^# - 1)/43], #, Nothing] &, Prime@Range @ 10000] (* Robert G. Wilson v, Nov 25 2017 *) PROG (PFGW) ABC2 (44^\$a-1)/43 // -f{2*\$a} a: primes from 2 to 1000000 (PARI) is(n) = ispseudoprime((44^n-1)/43) \\ Felix Fröhlich, Nov 08 2017 CROSSREFS Cf. A028491, A004061, A004062, A004063, A004023, A005808, A004064, A016054, A006032, A006033, A006034, A006035, A127995, A127996, A127997, A127998, A127999, A098438, A128002, A128003, A128004, A128005, A240765. Sequence in context: A092496 A045904 A034353 * A237622 A239334 A180635 Adjacent sequences: A294719 A294720 A294721 * A294723 A294724 A294725 KEYWORD nonn,more AUTHOR Paul Bourdelais, Nov 07 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 | Recents
The OEIS Community | Maintained by The OEIS Foundation Inc.

Last modified June 15 13:08 EDT 2024. Contains 373407 sequences. (Running on oeis4.)