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

 Hints (Greetings from The On-Line Encyclopedia of Integer Sequences!)
 A182132 Carmichael numbers of the form C = (30n-7)*(90n-23)*(300n-79). 1
 340561, 4335241, 153927961, 542497201, 1678569121, 2598933481, 3164207761, 25923026641, 63280622521, 88183003921, 155999871721, 209850699601, 240893092441, 274855097881, 380692027321, 733547013841, 1688729866321 (list; graph; refs; listen; history; text; internal format)
 OFFSET 1,1 COMMENTS Note that in this sequence, 30n-7, 90n-23, and 300n-79 do not have to be prime. Conjecture: The number C = (30n-7)*(90n-23)*(300n-79) is a Carmichael number if (but not only if) 30n-7, 90n-23 and 300n-79 are all three prime numbers. The conjecture is checked for 01 || vecmax(f2[, 2])>1 || vecmax(f3[, 2])>1, next); t=concat(concat(f1[, 1], f2[, 1]), f3[, 1]); for(i=1, #t, if((C-1)%(t[i]-1), next(2))); listput(v, C)); Vec(v) \\ Charles R Greathouse IV, Jun 29 2017 CROSSREFS Cf. A002997 (Carmichael numbers). Sequence in context: A236609 A103808 A251996 * A182515 A236703 A178900 Adjacent sequences: A182129 A182130 A182131 * A182133 A182134 A182135 KEYWORD nonn AUTHOR Marius Coman, Apr 14 2012 EXTENSIONS a(7) inserted by Charles R Greathouse IV, Jun 29 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 July 18 21:02 EDT 2024. Contains 374388 sequences. (Running on oeis4.)