This site is supported by donations to The OEIS Foundation.

 Please make a donation to keep the OEIS running. We are now in our 55th year. In the past year we added 12000 new sequences and reached 8000 citations (which often say "discovered thanks to the OEIS"). We need to raise money to hire someone to manage submissions, which would reduce the load on our editors and speed up editing. Other ways to donate

 Hints (Greetings from The On-Line Encyclopedia of Integer Sequences!)
 A129249 Primes of Erdos-Selfridge class 15-. 3
 1432349099, 1749565397, 2771868719, 3790874279, 5288908679, 5804138567, 6273146879, 8123301983, 8594094589, 11055501923, 11809566403, 11914176299, 12647401799, 13432673083, 13925010299, 14208729979 (list; graph; refs; listen; history; text; internal format)
 OFFSET 1,1 COMMENTS The fastest way to calculate the complete list of class N primes up to P is to use the given formula (or PARI function nextclass()) with the list of class (N-1) primes up to P/2. LINKS M. F. Hasler, Table of n, a(n) for n = 1..48 FORMULA { a(n) } = { p = 2*m*A129248(k)+1 | k=1,2,3... and m=1,2,3... such that p is prime and m has no factor of class > 14- } PROG (PARI) class(n, s=1) = { if(!isprime(n), 0, if(!(n=factor(n+s)[, 1]) || n[ #n]<=3, 1, for(i=2, #n, n[1]=max(class(n[i], s)+1, n[1])); n[1]))} nextclass(a, s=-1, p, n=[])={if(!p, p=nextprime(a[ #a]+1)); print("producing primes of class ", 1+class(a[1], s), ["+", "-"][1+(s<0)], " up to 2*", p); for(i=1, #a, for(k=1, p/a[i], if(isprime(2*k*a[i]-s), n=concat(n, 2*k*a[i]-s)))); vecsort(n)} A129249=nextclass(A129248) CROSSREFS Cf. A081640, A081641, A129248, A056637. Sequence in context: A185931 A069320 A274902 * A165736 A048051 A073519 Adjacent sequences:  A129246 A129247 A129248 * A129250 A129251 A129252 KEYWORD nonn AUTHOR M. F. Hasler, Apr 16 2007, Apr 21 2007 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 December 10 20:23 EST 2019. Contains 329909 sequences. (Running on oeis4.)