login
The OEIS is supported by the many generous donors to the OEIS Foundation.

 

Logo
Hints
(Greetings from The On-Line Encyclopedia of Integer Sequences!)
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 2
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 (list; graph; refs; listen; history; text; internal format)
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.

MAPLE

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

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.

License Agreements, Terms of Use, Privacy Policy. .

Last modified January 27 09:04 EST 2022. Contains 350607 sequences. (Running on oeis4.)