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!)
 A069561 Start of a run of n consecutive positive numbers divisible respectively by first n primes. 5
 2, 2, 8, 158, 788, 788, 210998, 5316098, 34415168, 703693778, 194794490678, 5208806743928, 138782093170508, 5006786309605868, 253579251611336438, 12551374903381164638, 142908008812141343558, 77053322014980646906358 (list; graph; refs; listen; history; text; internal format)
 OFFSET 1,1 COMMENTS It is evident that from a(3) onwards terms must be congruent to 8 mod p(3)#, where p(n)# is the n-th primorial (A002110). In fact the sequence for A069561(n) == k (mod p(n)#) for k: 2, 2, 8, 788, 788, 210988, etc. This follows from the Chinese Remainder Theorem. LINKS Charles R Greathouse IV, Table of n, a(n) for n = 1..350 FORMULA log a(n) << n log n. - Charles R Greathouse IV, Jun 20 2015 EXAMPLE a(5) = 788 as 788, 789, 790, 791 and 792 are divisible by 2, 3, 5, 7, and 11 respectively. MATHEMATICA f[n_] := ChineseRemainder[-Range[0, n - 1], Prime[Range[n]]]; Array[f, 17, 2] (* Robert G. Wilson v, Jan 13 2012 *) PROG (PARI) a(n)=lift(chinese(vector(max(n, 2), k, Mod(1-k, prime(k))))) \\ Charles R Greathouse IV, Jun 20 2015 CROSSREFS Cf. A072562. Sequence in context: A270405 A047692 A270316 * A180370 A326939 A011148 Adjacent sequences:  A069558 A069559 A069560 * A069562 A069563 A069564 KEYWORD nonn AUTHOR Amarnath Murthy, Mar 22 2002 EXTENSIONS More terms to a(15) from Sascha Kurz, Mar 23 2002 Edited and extended by Robert G. Wilson v, Aug 09 2002 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 February 22 05:54 EST 2020. Contains 332116 sequences. (Running on oeis4.)