login
The OEIS is supported by the many generous donors to the OEIS Foundation.

 

Logo
Hints
(Greetings from The On-Line Encyclopedia of Integer Sequences!)
A105049 a(n) is the smallest prime p such that p+n! is prime and p differs from all a(i), i<n. 2

%I #5 Mar 30 2012 17:39:00

%S 2,3,5,7,11,13,19,23,17,41,29,43,67,71,149,73,31,37,89,53,47,127,97,

%T 131,107,59,137,101,223,163,241,79,139,103,61,577,311,151,269,173,211,

%U 167,109,191,239,521,233,83,383,337,271,827,449,443,229,157,179,283,293,277

%N a(n) is the smallest prime p such that p+n! is prime and p differs from all a(i), i<n.

%C A variant of A130807.

%C If the requirement is dropped that a(n) be distinct from earlier primes in the list, the sequence becomes 2, 3, 5, 5, 7, 7, 11, 23, 17, 11, 17, 29, 67, 19, 43, 23, 31, 37, 89,.. which presumably duplicates A037153.

%p A105049 := proc(nmin) local i,a,iused; a := [] ; iused := {} ; for n from 1 to nmin do i := 1; while not isprime(ithprime(i)+n!) or i in iused do i := i+1 ; od; iused := iused union {i} ; a := [op(a),ithprime(i)] ; od ; RETURN(a) ; end: A105049(80);

%K nonn

%O 1,1

%A _R. J. Mathar_, Aug 22 2007

Lookup | Welcome | Wiki | Register | Music | Plot 2 | Demos | Index | Browse | More | WebCam
Contribute new seq. or comment | Format | Style Sheet | Transforms | Superseeker | Recents
The OEIS Community | Maintained by The OEIS Foundation Inc.

License Agreements, Terms of Use, Privacy Policy. .

Last modified March 28 12:26 EDT 2024. Contains 371254 sequences. (Running on oeis4.)