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A370158
a(n) is the number of prime quadruples of the form {p, p+2, p+6, p+12} with p < 10^n.
0
0, 1, 4, 8, 24, 76, 313, 1644, 9397, 56734, 361386, 2417777, 16785520, 120150723, 882578840
OFFSET
0,3
COMMENTS
These quadruples are adjacent twin/cousin/sexy prime pairs, and may consist of non-consecutive primes (see A086140).
EXAMPLE
The third term, the count of quad primes < 10^2, is 4 and they are: (5,7,11,17), (11,13,17,23), (17,19,23,29), (41,43,47,53). The first term, the count of quad primes <10^0, is 0 since the smallest prime is 2.
PROG
(Perl) use ntheory ':all'; use bigint; sub a { my $count = () = sieve_prime_cluster(1, 10**$_[0], 2, 6, 12) }; $| = 1; for (0..12) { print(a($_), ", ") } # Daniel Suteu, Feb 23 2024
CROSSREFS
KEYWORD
nonn,more
AUTHOR
James S. DeArmon, Feb 10 2024
EXTENSIONS
a(8)-a(11) from Hugo Pfoertner, Feb 10 2024
a(12) from Daniel Suteu, Feb 23 2024
a(13)-a(14) from Martin Ehrenstein, Feb 29 2024
STATUS
approved