A145174 Least a(n) such that p(n)#*(p(n)#-a(n))-1 and p(n)#*(p(n)#-a(n))+1 are twin primes with p(i)#=i-th primorial.

0, 1, 3, 1, 5, 4, 44, 13, 31, 173, 25, 19, 75, 99, 47, 77, 166, 468, 43, 1, 344, 7, 44, 398, 434, 901, 246, 246, 91, 755, 1066, 839, 1605, 560, 460, 1649, 426, 1203, 732, 1055, 130, 1821, 1645, 360, 4779, 2414, 272, 668, 2410, 3957, 2514, 685, 3484, 3139, 5680

Offset

1,3

Links

Pierre CAMI, Table of n, a(n) for n = 1..200

Example

a(2) = 1 because 2*3*(2*3-1)-1 = 29 and 31 are prime.

Crossrefs

Cf. A002110, A144946, A144947, A145173.

Sequence in context: A007085 A094648 A096975 * A372283 A351965 A228785

Adjacent sequences: A145171 A145172 A145173 * A145175 A145176 A145177

Keyword

nonn

Author

Pierre CAMI, Oct 03 2008

Extensions

Corrected and extended by Ray Chandler, Jan 12 2009

Status

approved