The OEIS Foundation is supported by donations from users of the OEIS and by a grant from the Simons Foundation.

 Hints (Greetings from The On-Line Encyclopedia of Integer Sequences!)
 A296522 Number of disjoint covering systems of cardinality n with gcd of the moduli equal to 1. 0
 1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 30 (list; graph; refs; listen; history; text; internal format)
 OFFSET 1,13 COMMENTS A disjoint covering system (DCS) is a system of congruences of the form x == a_i (mod m_i) such that every integer lies in exactly one of the congruences. Here the "moduli" are the m_i. LINKS I. P. Goulden, L. B. Richmond, and J. Shallit, Natural exact covering systems and the reversion of the MÃ¶bius series, arXiv:1711.04109 [math.NT], 2017. EXAMPLE An example of one of the 30 DCS with GCD 1 counted by a(13) is as follows: x == 0,2 (mod 6) x == 1,3,5,7 (mod 10) x == 4 (mod 15) x == 9,10,16,22,28,29 (mod 30) Note that gcd(6,10,15,30) = 1. CROSSREFS Sequence in context: A219015 A144839 A124992 * A023926 A022068 A277043 Adjacent sequences:  A296519 A296520 A296521 * A296523 A296524 A296525 KEYWORD nonn,more AUTHOR Jeffrey Shallit, Dec 14 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 | Recent
The OEIS Community | Maintained by The OEIS Foundation Inc.

Last modified August 5 08:27 EDT 2021. Contains 346464 sequences. (Running on oeis4.)