A093077
Primes p = prime(i) such that p(i)# + p(i+1) is prime.
Original entry on oeis.org
2, 3, 5, 13, 17, 19, 43, 53, 59, 73, 367, 6143
Offset: 1
3 = p(2) is in the sequence because p(2)# + p(3) = 11 is prime.
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Do[p = Product[ Prime[i], {i, 1, n}]; q = Prime[n + 1]; If[ PrimeQ[p + q], Print[ Prime[n]]], {n, 1, 1435}]
With[{nn=1000},NextPrime[#,-1]&/@(Select[Thread[{FoldList[ Times,Prime[ Range[nn]]],Prime[Range[ 2,nn+1]]}], PrimeQ[ Total[#]]&][[All,2]])] (* Harvey P. Dale, Oct 07 2018 *)
A249798
Numbers k such that the product of the first k primes minus the (k+1)-th prime is prime.
Original entry on oeis.org
3, 4, 5, 6, 8, 22, 23, 24, 35, 73, 83, 147, 553, 1098, 1115, 1542, 2097, 2149, 8712, 19965, 25046, 30987, 38635
Offset: 1
p(1)*p(2)*p(3)*p(4) - p(5) = 2*3*5*7 - 11 = 199. 199 is prime, therefore 4 is in the sequence.
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Select[Range[1000],PrimeQ[Times@@(Prime[Range[#]])-Prime[#+1]]&]
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lista(nn) = {prp = 1; for(n=1, nn, prp *= prime(n); if (isprime(prp-prime(n+1)), print1(n, ", ")););} \\ Michel Marcus, Nov 06 2014
A367182
Primes of the form (k-th primorial) - (k+1)st prime.
Original entry on oeis.org
23, 199, 2297, 30013, 9699667, 3217644767340672907899084554047, 267064515689275851355624017992701, 23768741896345550770650537601358213, 1492182350939279320058875736615841068547583863326864530259
Offset: 1
primorial(4) - prime(4+1) = 2*3*5*7 - prime(5) = 210 - 11 = 199, which is prime, so 199 is a term.
A038708 with subtraction instead of addition.
Showing 1-3 of 3 results.
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