A128661 Numbers k such that p(k+1)# + p(k)# - p(k-1)# - 1 is prime where p(i)# = product of first i primes = A002110(i).

3, 7, 14, 15, 21, 32, 34, 47, 67, 69, 174, 369, 568, 3193, 3882, 5426

Offset

1,1

Links

Table of n, a(n) for n=1..16.

Mathematica

Flatten[Position[Partition[Rest[FoldList[Times, 1, Prime[Range[ 600]]]], 3, 1], _?(PrimeQ[#[[3]]+#[[2]]-#[[1]]-1]&), {1}, Heads-> False]]+1 (* Harvey P. Dale, May 26 2013 *)

Crossrefs

Cf. A002110, A128420, A128421, A128657, A128658, A128659, A128660, A128662.

Sequence in context: A089305 A112618 A058027 * A175339 A361969 A009461

Adjacent sequences: A128658 A128659 A128660 * A128662 A128663 A128664

Keyword

nonn,more

Author

Pierre CAMI, Mar 19 2007

Extensions

a(14)-a(16) from Michael S. Branicky, Jul 22 2023

Status

approved