login
This site is supported by donations to The OEIS Foundation.

 

Logo

Annual Appeal: Please make a donation (tax deductible in USA) to keep the OEIS running. Over 5000 articles have referenced us, often saying "we discovered this result with the help of the OEIS".

Hints
(Greetings from The On-Line Encyclopedia of Integer Sequences!)
A115396 Smallest prime p such that p-/+2n are semiprimes. 0
23, 29, 71, 17, 59, 37, 71, 41, 67, 71, 43, 109, 59, 67, 173, 83, 89, 151, 103, 89, 127, 101, 131, 113, 127, 109, 131, 113, 127, 193, 157, 157, 181, 179, 229, 163, 193, 191, 211, 223, 223, 239, 241, 211, 211, 211, 271, 281, 241, 241, 263, 307, 307, 373, 293 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

COMMENTS

Cf. A063643 Primes p such that p+/-2 are semiprimes, A117328 Primes p such that p+/-4 are semiprimes.

LINKS

Table of n, a(n) for n=1..55.

EXAMPLE

a(100)=571 because 571-2*100=371=7*53 (semiprime), 571+2*100=771=3*257 (semiprime).

CROSSREFS

Cf. A063643.

Sequence in context: A157677 A092518 A110584 * A180538 A227217 A229176

Adjacent sequences:  A115393 A115394 A115395 * A115397 A115398 A115399

KEYWORD

nonn

AUTHOR

Zak Seidov, Mar 08 2006

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 | More pages
The OEIS Community | Maintained by The OEIS Foundation Inc.

License Agreements, Terms of Use, Privacy Policy .

Last modified December 6 12:43 EST 2016. Contains 278781 sequences.