A188366 Values of c such that (c+9*b)*Prime(n)#-1 is the least prime such that (c+k*b)*Prime(n)#-1 is prime for k=0 to 9 with c+9*b < Prime(n)# , or 0 if no solution. Prime(n)#=n-th primorial

0, 0, 0, 0, 0, 653, 1542, 2035, 2460, 7473, 654, 7394, 7479, 69698, 4646, 25205, 122774, 42953, 444644, 38761, 545933, 83675, 212892, 87123, 106714, 50427, 747235, 1737780, 2371271, 1807313

Offset

1,6

Comments

b=A188367(n), c*Prime(n)#-1 is the first of an arithmetic progression of 10 primes or more.

I use PFGW program from primeform group to generate the primes and my own sieve to find the least sum c+9*b for an arithmetic progression of at least 10 primes, all primes are certified primes by PFGW program.

Links

Table of n, a(n) for n=1..30.

Example

13#=30030, 30030*653-1=19609589 , 289*30030=8678670
196095899+k*8678670 is prime for k=0 to 9 for n=6 c=653
and b=289

Crossrefs

Cf. A188367.

Sequence in context: A198170 A145125 A145202 * A255208 A060520 A250701

Adjacent sequences: A188363 A188364 A188365 * A188367 A188368 A188369

Keyword

nonn,hard

Author

Pierre CAMI, Mar 29 2011

Extensions

More terms from Pierre CAMI

Status

approved