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A115785 Smallest prime number p such that p - p(1)#, p - p(2)#, ..., p - p(n)# are all prime, where p(i)# is the primorial of the i-th prime (A002110(i)). 1

%I #9 Apr 03 2023 10:36:11

%S 5,13,43,229,3463,43789,1088449,19800379,264333259,9348884059,

%T 228178314439,7931712374479,307867708410673,13230211614496609,

%U 618681508598750923

%N Smallest prime number p such that p - p(1)#, p - p(2)#, ..., p - p(n)# are all prime, where p(i)# is the primorial of the i-th prime (A002110(i)).

%C Subset of A006512 (greater of twin primes).

%C Inspired by C. Rivera's Prime Curio for 313. a(4) = 229 is the smallest prime having the same property he states for 313.

%H G. L. Honaker, Jr. and Chris Caldwell, <a href="https://t5k.org/curios/cpage/5730.html">Prime Curios! 313</a>

%H C. Rivera, <a href="http://www.primepuzzles.net/puzzles/puzz_350.htm">Puzzle 350. Primes & primorials</a>.

%e a(4) = 229 because 229, 229 - 2, 229 - 2*3, 229 - 2*3*5 and 229 - 2*3*5*7 are all prime and there is no smaller prime with this property.

%Y Cf. A002110, A006512, A115786 (for p + p(i)#).

%K more,nonn

%O 1,1

%A _Rick L. Shepherd_, Jan 31 2006

%E a(10) from _Don Reble_, Feb 15 2006

%E More terms from _Jens Kruse Andersen_, Feb 26 2006

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Last modified April 25 07:53 EDT 2024. Contains 371964 sequences. (Running on oeis4.)