A129249 Primes of Erdos-Selfridge class 15-.

1432349099, 1749565397, 2771868719, 3790874279, 5288908679, 5804138567, 6273146879, 8123301983, 8594094589, 11055501923, 11809566403, 11914176299, 12647401799, 13432673083, 13925010299, 14208729979

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

Index entries for sequences related to the Erdos-Selfridge classification

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

Sequence in context: A185931 A069320 A274902 * A165736 A048051 A345337

Adjacent sequences: A129246 A129247 A129248 * A129250 A129251 A129252

Keyword

nonn

Author

M. F. Hasler, Apr 16 2007, Apr 21 2007

Status

approved