

A055738


Number of prime quadruples < 10^n, where a prime quadruple means 4 successive primes {p, p', p'', p'''} with p''' = p + 8.


1



0, 3, 6, 13, 39, 167, 900, 4769, 28389, 180530, 1209319, 8398279, 60070591, 441296837, 3314576488
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OFFSET

1,2


REFERENCES

J. Recreational Math., vol. 23, No. 2, 1991, p. 97.


LINKS



EXAMPLE

For n=2 the quadruples are 3,5,7,11; 5,7,11,13; 11,13,17,19.


MAPLE

with(numtheory): x := 1229; t1 := [seq(ithprime(i), i=1..x)]; c := 0: for i from 1 to x3 do if t1[i]+8 = t1[i+3] then c := c+1; fi; od: c; # the values of x to use are given by A006880.


MATHEMATICA

x=168; a=Table[ Prime[ n ], {n, 1, x} ]; c=0; Do[ If[ a[ [ n ] ]+8==a[ [ n+2 ] ], c++ ], {n, 1, x3} ]; # the values of x to use are given by A006880.


CROSSREFS



KEYWORD

nonn


AUTHOR



EXTENSIONS



STATUS

approved



