login
The OEIS Foundation is supported by donations from users of the OEIS and by a grant from the Simons Foundation.

 

Logo


Hints
(Greetings from The On-Line Encyclopedia of Integer Sequences!)
A175893 a(n) = m such that 2*prime(m)+prime(m+1) is prime. 0
1, 2, 3, 6, 7, 8, 10, 17, 22, 27, 29, 30, 35, 45, 48, 49, 50, 52, 53, 57, 61, 68, 70, 80, 81, 85, 94, 104, 106, 117, 120, 125, 126, 127, 131, 132, 136, 137, 138, 143, 146, 156, 157, 166, 177, 191, 198, 206, 220, 223, 224, 225, 233, 236, 244, 248, 254, 259, 261, 262 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,2

LINKS

Table of n, a(n) for n=1..60.

FORMULA

a(n) = pi(A173971(n))=A000720(A173971(n)).

PROG

(PARI) {a=2; for(n=1, 1000, b=nextprime(a+1); isprime(2*a+b)&print1(n, ", "); a=b)

CROSSREFS

Cf. A000040 The prime numbers.

A173971 Primes p such that 2*p+NextPrime are prime numbers.

A000720 pi(n), the number of primes <= n.

Sequence in context: A119960 A273265 A015841 * A031470 A047223 A004435

Adjacent sequences:  A175890 A175891 A175892 * A175894 A175895 A175896

KEYWORD

easy,nonn

AUTHOR

Zak Seidov, Oct 10 2010

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 September 22 03:20 EDT 2021. Contains 347605 sequences. (Running on oeis4.)