|
| |
|
|
A136019
|
|
Smallest prime of the form (prime(k)+2*n)/(2*n+1), any k.
|
|
55
| |
|
|
3, 3, 5, 3, 3, 5, 3, 7, 11, 3, 3, 5, 5, 3, 11, 3, 3, 5, 3, 3, 5, 5, 7, 5, 3, 3, 7, 5, 13, 7, 3, 3, 5, 3, 13, 5, 3, 7, 5, 3, 3, 13, 5, 3, 7, 5, 3, 5, 3, 7, 7, 3, 7, 11, 3, 3, 5, 11, 3, 7, 7, 3, 5, 11, 3, 13, 3, 7, 5, 3, 7, 11, 7, 13, 7, 3, 3, 11, 23, 7, 5, 3, 31, 5, 13, 3, 5, 5, 3, 7, 3, 13, 7, 3, 3, 5, 7
(list; graph; refs; listen; history; internal format)
|
|
|
|
OFFSET
| 1,1
|
|
|
COMMENTS
| The associated prime(k) are in A136020.
|
|
|
EXAMPLE
| a(1)=3 because 3 is smallest prime of the form (p+2)/3; in this case prime(k)=7.
a(2)=3 because 3 is smallest prime of the form (p+4)/5; in this case prime(k)=11.
a(3)=5 because 5 is smallest prime of the form (p+6)/7; in this case prime(k)=29.
|
|
|
MATHEMATICA
| a = {}; Do[k = 1; While[ !PrimeQ[(Prime[k] + 2n)/(2n + 1)], k++ ]; AppendTo[a, (Prime[k] + 2n)/(2n + 1)], {n, 1, 200}]; a
|
|
|
PROG
| (PARI) a(n)=my(N=2*n, k=0, t); forprime(p=2, default(primelimit), k++; t=(p+N)/(N+1); if(denominator(t)==1&isprime(t), return(t))) \\ Charles R Greathouse IV, Jun 16 2011
|
|
|
CROSSREFS
| Cf. A136020, A136026, A136027.
Sequence in context: A020483 A138479 A202106 * A063714 A113965 A162277
Adjacent sequences: A136016 A136017 A136018 * A136020 A136021 A136022
|
|
|
KEYWORD
| nonn,easy
|
|
|
AUTHOR
| Artur Jasinski (grafix(AT)csl.pl), Dec 10 2007
|
|
|
EXTENSIONS
| Edited by R. J. Mathar (mathar(AT)strw.leidenuniv.nl), May 17 2009
|
| |
|
|
