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A059960 Smaller term of a pair of twin primes such that prime factors of their average are only 2 and 3. 17
5, 11, 17, 71, 107, 191, 431, 1151, 2591, 139967, 472391, 786431, 995327, 57395627, 63700991, 169869311, 4076863487, 10871635967, 2348273369087, 56358560858111, 79164837199871, 84537841287167, 150289495621631 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

COMMENTS

Primes p(k) such that the number of distinct prime divisors of all composite numbers between p(k) and p(k+1) is 2. - Amarnath Murthy, Sep 26 2002

LINKS

Ray Chandler, Table of n, a(n) for n = 1..61 (terms < 10^1000, first 49 terms from T. D. Noe)

FORMULA

Primes p such that p+1 = (2^u)*(3^w)

EXAMPLE

a(11)+1 = 2*2*2*3*3*3*3*3*3*3*3*3*3 = 472392.

MATHEMATICA

nn=10^15; Sort[Reap[Do[n=2^i 3^j; If[n<=nn && PrimeQ[n-1] && PrimeQ[n+1], Sow[n-1]], {i, Log[2, nn]}, {j, Log[3, nn]}]][[2, 1]]]

CROSSREFS

Cf. A014574, A002822, A033845, A058383, A027856.

Cf. A052297, A075581, A075580, A075583, A075584, A075585, A075586, A075587, A075588, A075589.

Apart from initial terms, same as A078883.

Sequence in context: A058019 A182482 A075582 * A265850 A185365 A282669

Adjacent sequences:  A059957 A059958 A059959 * A059961 A059962 A059963

KEYWORD

nonn

AUTHOR

Labos Elemer, Mar 02 2001

STATUS

approved

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Last modified October 18 00:21 EDT 2019. Contains 328135 sequences. (Running on oeis4.)