A128660 Numbers n such that p(n+1)#-p(n)#-p(n-1)#+1 is prime where p(i)#=product of first i primes=A002110(i).

2, 6, 14, 15, 23, 31, 97, 144, 983, 2587, 3163, 6689

Offset

1,1

Links

Table of n, a(n) for n=1..12.

Mathematica

Flatten[Position[#[[3]]-#[[2]]-#[[1]]+1&/@Partition[FoldList[Times, 1, Prime[ Range[ 6700]]] , 3, 1], _?PrimeQ]] (* Harvey P. Dale, Jul 25 2013 *)

Crossrefs

Cf. A002110, A128420, A128421, A128657, A128658, A128659, A128661, A128662.

Sequence in context: A160657 A222087 A293654 * A212719 A145213 A050859

Adjacent sequences: A128657 A128658 A128659 * A128661 A128662 A128663

Keyword

nonn

Author

Pierre CAMI, Mar 19 2007

Status

approved