This site is supported by donations to The OEIS Foundation.

Annual Appeal: Today, Nov 11 2014, is the 4th anniversary of the launch of the new OEIS web site. 70,000 sequences have been added in these four years, all edited by volunteers. Please make a donation (tax deductible in the US) to help keep the OEIS running.

 Hints (Greetings from The On-Line Encyclopedia of Integer Sequences!)
 A074379 Super-Carmichael numbers with exactly 4 factors. 2
 41041, 62745, 63973, 75361, 101101, 126217, 172081, 188461, 278545, 340561, 449065, 552721, 656601, 658801, 670033, 748657, 838201, 852841, 997633, 1033669, 1082809, 1569457, 1773289, 2100901, 2113921, 2433601, 2455921 (list; graph; refs; listen; history; text; internal format)
 OFFSET 1,1 COMMENTS Super-Carmichael numbers are Carmichael numbers (A002997) for which Moebius function mu(n) is 1 (A008683). There are no super-Carmichael numbers with exactly 2 factors since Carmichael numbers must have at least 3 factors. LINKS R. J. Mathar, Table of n, a(n) for n = 1..6042 EXAMPLE 41041 = 7 * 11 * 13 * 41, 62745 = 3 * 5 * 47 * 89, ... MATHEMATICA p = Table[ Prime[i], {i, 1, 10}]; f[n_] := Union[ PowerMod[ Select[p, GCD[ #, n] == 1 & ], n - 1, n]]; Select[ Range[2500000], !PrimeQ[ # ] && OddQ[ # ] && Length[ FactorInteger[ # ]] == 4 && MoebiusMu[ # ] == 1 && f[ # ] == {1} & ] CROSSREFS Cf. A002997, A006931. Sequence in context: A173361 A047828 A141711 * A237395 A234546 A183667 Adjacent sequences:  A074376 A074377 A074378 * A074380 A074381 A074382 KEYWORD nonn AUTHOR Jani Melik, Sep 24 2002 EXTENSIONS Edited and extended by Robert G. Wilson v, Oct 03 2002 STATUS approved

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

Content is available under The OEIS End-User License Agreement .