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!)
A229570 Primes of form p*q + 30, where p and q are consecutive primes. 1

%I #11 Mar 14 2015 13:55:02

%S 107,173,251,353,467,929,2521,4787,7417,8663,10433,12347,17977,19073,

%T 25621,28921,32429,39233,42019,50651,55717,60521,77867,95507,97373,

%U 99251,111577,116969,126757,131783,141397,159227,164039,171401,186653,194507,198937,205223

%N Primes of form p*q + 30, where p and q are consecutive primes.

%C Conjecture: The expression p*q + c with p and q consecutive primes and c = 30 generates more primes than any other value of c in the range 1 < c < 100 and p = 48611 which is 5000th prime. Hence, c = 30 is considered for this sequence.

%H K. D. Bajpai, <a href="/A229570/b229570.txt">Table of n, a(n) for n = 1..1000</a>

%e a(1)=107: prime(4)*prime(5)+30=107, which is prime.

%e a(6)=929: prime(10)*prime(11)+30=929, which is prime.

%p KD:= proc() local a; a:= ithprime(n)*ithprime(n+1)+30; if isprime((a)) then RETURN((a)):fi;end: seq(KD(),n=1..500);

%t Select[Table[Prime[n]*Prime[n+1]+30,{n,100}],PrimeQ]

%Y Cf. A048880.

%K nonn

%O 1,1

%A _K. D. Bajpai_, Sep 26 2013

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 August 31 13:44 EDT 2024. Contains 375567 sequences. (Running on oeis4.)