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A141561 Primes of the form (7*n-p(n)), where p(n)=n-th prime. 1
5, 11, 29, 37, 41, 47, 59, 79, 89, 97, 101, 103, 107, 113, 113, 127, 139, 137, 139, 149, 149, 151, 167, 167, 157, 163, 179, 179, 181, 181, 181, 181, 181, 179, 173, 181, 179, 191, 181, 179, 181, 179, 179, 191, 191, 193, 193, 179, 181, 179, 173, 179, 173, 179 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

COMMENTS

For n>=1, list 7*k-prime(k) if abs(7*k-prime(k)) is prime. Terms are negative for n >= 114. - Joerg Arndt, Sep 03 2020

Some terms appear many times. For example, in the first 1000 terms, 179 appears 12 times. There are only 755 distinct terms in the first 1000 terms. - Harvey P. Dale, Aug 15 2020

LINKS

Harvey P. Dale, Table of n, a(n) for n = 1..1000

EXAMPLE

If n=1, then 7*1-p(1)=7-2=5=a(1).

If n=2, then 7*2-p(2)=14-3=11=a(2).

If n=3, then 7*3-p(3)=21-5=16 (composite).

If n=4, then 7*4-p(4)=28-7=21 (composite).

If n=5, then 7*5-p(5)=35-11=25 (composite).

If n=6, then 7*6-p(6)=42-13=29=a(3).

If n=7, then 7*7-p(7)=49-17=32 (composite).

If n=8, then 7*8-p(8)=56-19=37=a(4).

If n=9, then 7*9-p(9)=63-23=40 (composite).

If n=10, then 7*10-p(10)=70-29=41=a(5).

If n=11, then 7*11-p(11)=77-31=46 (composite).

If n=12, then 7*12-p(12)=84-37=47=a(6).

If n=13, then 7*13-p(13)=91-41=50 (composite).

If n=14, then 7*14-p(14)=98-43=55 (composite).

If n=15, then 7*15-p(15)=105-47=58 (composite).

If n=16, then 7*16-p(16)=112-53=59=a(7), etc.

MATHEMATICA

Select[Table[7n-Prime[n], {n, 250}], PrimeQ] (* Harvey P. Dale, Aug 15 2020 *)

CROSSREFS

Cf. A000040.

Sequence in context: A291279 A182379 A243544 * A240103 A019345 A279067

Adjacent sequences:  A141558 A141559 A141560 * A141562 A141563 A141564

KEYWORD

sign,less,dumb

AUTHOR

Juri-Stepan Gerasimov, Aug 14 2008

EXTENSIONS

Edited, corrected and extended by Ray Chandler, Aug 19 2008

STATUS

approved

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Last modified January 18 18:15 EST 2021. Contains 340254 sequences. (Running on oeis4.)