A120120 Number of n-digit prime quadruplets.

1, 3, 7, 26, 128, 733, 3869, 23620, 152141, 1028789, 7188960, 51672312, 381226246, 2873279651

Offset: 2

Author

Julien Peter Benney (jpbenney(AT)ftml.net), Aug 15 2006, Aug 19 2006

Keywords

• nonn
• more
• base

Examples

			a(3) = 3 because there are three three-digit prime quadruples: {101, 103, 107, 109}, {191, 193, 197, 199} and {821, 823, 827, 829}.
		

Links

• J.-L. Baril, Classical sequences revisited with permutations avoiding dotted pattern, Electronic Journal of Combinatorics, 18 (2011), #P178.
• Thomas R. Nicely, Enumeration to 1.6*10^15 of the prime quadruplets.

Crossrefs

Cf. A006879, A070076, A038801.

Extensions

a(6) corrected and a(15) supplied by Jon E. Schoenfield, Aug 27 2006