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

 Hints (Greetings from The On-Line Encyclopedia of Integer Sequences!)
 A333130 Numbers that are super pseudoprimes to both bases 2 and 3. 2
 2701, 18721, 31621, 49141, 83333, 90751, 104653, 226801, 282133, 653333, 665281, 721801, 873181, 1373653, 1530787, 1537381, 1584133, 1690501, 1755001, 1987021, 2008597, 2035153, 2284453, 2746589, 2944261, 3059101, 3116107, 3363121, 3375041, 3375487, 4082653, 4314967 (list; graph; refs; listen; history; text; internal format)
 OFFSET 1,1 COMMENTS The first term that has more than 2 prime factors is a(1067) = A333131(1) = 11500521553. The first term that is also a Carmichael number is a(1131) = 13079177569. LINKS Amiram Eldar, Table of n, a(n) for n = 1..10000 EXAMPLE 2701 is a term since it is a Fermat pseudoprime to both bases 2 and 3, and its proper divisors that are larger than 1 are all primes: 37 and 73. MATHEMATICA pspQ[n_] := CompositeQ[n] && AllTrue[Rest @ Divisors[n], PowerMod[2, # - 1, #] == 1 && PowerMod[3, # - 1, #] == 1 &]; Select[Range[10^6], pspQ] CROSSREFS Intersection of A050217 and A328662. Subsequence of A001567, A005935, A052155 and A153513. Sequence in context: A230752 A246888 A153513 * A214016 A254513 A254506 Adjacent sequences: A333127 A333128 A333129 * A333131 A333132 A333133 KEYWORD nonn AUTHOR Amiram Eldar, Mar 08 2020 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 March 24 11:01 EDT 2023. Contains 361479 sequences. (Running on oeis4.)