The OEIS is supported by the many generous donors to the OEIS Foundation. Hints (Greetings from The On-Line Encyclopedia of Integer Sequences!)
 A136349 Numbers k of the form Product_{j=1..m} prime(j) such that k-1 is prime. 10
 6, 30, 2310, 30030, 304250263527210, 23768741896345550770650537601358310 (list; graph; refs; listen; history; text; internal format)
 OFFSET 1,1 COMMENTS This sequence is different from A121069 and A002110. Compute the product of k consecutive sequences of prime factors 2,3,5,7, etc. where k=1,2,3,4,5, etc. When N is preceded by prime N-1 add N to the sequence. a(7) = 1 9361386640 7008231634 7142505431 2320082662 8976125715 6376190696 2414215012 3698566371 7909694733 5243680669 6075314756 2914824028 4399976570 - copied from Data field by Michael B. Porter, Mar 30 2013 Next term (a(8)) is too large to be included: see A006794. - M. F. Hasler, May 02 2008 The next 7 terms in the sequence are a(7) = p# 2..89 (shown in full above), a(8) = p# 2..317, a(9) = p# 2..337, a(10) = p# 2..991, a(11) = p# 2..1873, a(12) = p# 2..2053, a(13) = p# 2..2377, where p# indicates a primorial. - Jeff Hall, Apr 05 2021 LINKS Table of n, a(n) for n=1..6. FORMULA a(n) = A057705(n) + 1 = A034386( A006794(n) ). - M. F. Hasler, May 02 2008 EXAMPLE a(3)=30 where the prime factors are 2,3,5; since N-1=29, prime, N=30 is added to the sequence. MATHEMATICA Select[FoldList[Times, 1, Prime[Range]], PrimeQ[#-1]&] (* Harvey P. Dale, Jan 09 2011 *) PROG (PARI) c=0; t=1; vector(7, n, until( ispseudoprime( -1+t*=prime(c++)), ); t) CROSSREFS Cf. A136350, A136351, A136352, A002110, A121069. Sequence in context: A200894 A202861 A088256 * A119411 A036285 A101340 Adjacent sequences: A136346 A136347 A136348 * A136350 A136351 A136352 KEYWORD nonn AUTHOR Enoch Haga, Dec 25 2007 EXTENSIONS Edited by M. F. Hasler, May 02 2008, May 30 2008 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 September 30 06:20 EDT 2023. Contains 365781 sequences. (Running on oeis4.)