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 A120120 Number of n-digit prime quadruplets. 3
 1, 3, 7, 26, 128, 733, 3869, 23620, 152141, 1028789, 7188960, 51672312, 381226246, 2873279651 (list; graph; refs; listen; history; text; internal format)
 OFFSET 2,2 LINKS Table of n, a(n) for n=2..15. 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. EXAMPLE a(3) = 3 because there are three three-digit prime quadruples: {101, 103, 107, 109}, {191, 193, 197, 199} and {821, 823, 827, 829}. CROSSREFS Cf. A006879, A070076, A038801. Sequence in context: A158561 A252786 A108217 * A126472 A019059 A305446 Adjacent sequences: A120117 A120118 A120119 * A120121 A120122 A120123 KEYWORD nonn,more,base AUTHOR Julien Peter Benney (jpbenney(AT)ftml.net), Aug 15 2006, Aug 19 2006 EXTENSIONS a(6) corrected and a(15) supplied by Jon E. Schoenfield, Aug 27 2006 STATUS approved

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Last modified June 21 12:41 EDT 2024. Contains 373544 sequences. (Running on oeis4.)