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

 Hints (Greetings from The On-Line Encyclopedia of Integer Sequences!)
 A031157 Numbers that are both lucky and prime. 22
 3, 7, 13, 31, 37, 43, 67, 73, 79, 127, 151, 163, 193, 211, 223, 241, 283, 307, 331, 349, 367, 409, 421, 433, 463, 487, 541, 577, 601, 613, 619, 631, 643, 673, 727, 739, 769, 787, 823, 883, 937, 991, 997, 1009, 1021, 1039, 1087, 1093, 1117, 1123 (list; graph; refs; listen; history; text; internal format)
 OFFSET 1,1 COMMENTS A010051(a(n))*A145649(a(n)) = 1. - Reinhard Zumkeller, Oct 19 2008 Conjecture: This sequence is infinite. - Ahmad J. Masad, Feb 17 2020 Conjecture: If this sequence is infinite, then there exists a minimum sufficiently large integer k, such that for all a(n) > k, there exists a positive integer x and there exists m>n such that x(x-1) < a(n) < x^2 and x^2 < a(m) < x(x+1). This conjecture is similar to Oppermann's conjecture. - Ahmad J. Masad, Jun 23 2020 LINKS T. D. Noe, Table of n, a(n) for n = 1..10000 Wikipedia, Lucky prime MATHEMATICA luckies = Range[1, 1248, 2]; i = 2; While[ i <= (len = Length@luckies) && (k = luckies[[i]]) <= len, luckies = Drop[luckies, {k, len, k}]; i++ ]; Select[luckies, PrimeQ@# &] (* Robert G. Wilson v, May 12 2006 *) CROSSREFS Cf. A000959, A055728. Sequence in context: A249378 A136060 A023227 * A049488 A136051 A100750 Adjacent sequences: A031154 A031155 A031156 * A031158 A031159 A031160 KEYWORD nonn AUTHOR Patrick De Geest 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 September 25 14:51 EDT 2023. Contains 365648 sequences. (Running on oeis4.)