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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
J.-L. Baril, Classical sequences revisited with permutations avoiding dotted pattern, Electronic Journal of Combinatorics, 18 (2011), #P178.
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
Sequence in context: A158561 A252786 A108217 * A126472 A019059 A305446
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.)