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!)
A049613 a(n) = 2n - (largest prime < 2n-2). 6
3, 3, 3, 5, 3, 3, 5, 3, 3, 5, 3, 5, 7, 3, 3, 5, 7, 3, 5, 3, 3, 5, 3, 5, 7, 3, 5, 7, 3, 3, 5, 7, 3, 5, 3, 3, 5, 7, 3, 5, 3, 5, 7, 3, 5, 7, 9, 3, 5, 3, 3, 5, 3, 3, 5, 3, 5, 7, 9, 11, 13, 15, 3, 5, 3, 5, 7, 3, 3, 5, 7, 9, 11, 3, 3, 5, 7, 3, 5, 7, 3, 5, 3, 5, 7, 3, 5, 7, 3, 3, 5 (list; graph; refs; listen; history; text; internal format)
OFFSET

3,1

LINKS

T. D. Noe, Table of n, a(n) for n=3..10000

FORMULA

a(n) <= A002373(n). - R. J. Mathar, Mar 19 2008

a(n) = 2*n - A007917(2*n-2). - Reinhard Zumkeller, Jan 02 2015

EXAMPLE

a(14)=28 - (largest prime < 26) = 28 - 23 = 5.

MATHEMATICA

Table[2n-NextPrime[2n-2, -1], {n, 3, 100}] (* Harvey P. Dale, Aug 16 2011 *)

PROG

(Haskell)

a049613 n = 2 * n - a007917 (2 * n - 2)

-- Reinhard Zumkeller, Jan 02 2015

CROSSREFS

Cf. A049653, A049711, A049716, A049847.

Cf. A002373, A020481, A007917.

Sequence in context: A242033 A301738 A302387 * A002373 A236569 A103153

Adjacent sequences:  A049610 A049611 A049612 * A049614 A049615 A049616

KEYWORD

nice,nonn,easy

AUTHOR

David M. Elder (elddm(AT)rhodes.edu)

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 29 17:14 EDT 2020. Contains 337432 sequences. (Running on oeis4.)