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A230482 (prime(prime(2n)) - prime(2 prime(n)))/2. 2
-1, 2, 6, 12, 15, 28, 26, 39, 42, 41, 54, 44, 63, 72, 63, 81, 75, 102, 105, 105, 124, 121, 117, 174, 133, 134, 160, 181, 190, 197, 152, 198, 170, 240, 189, 210, 233, 243, 238, 232, 249, 289, 238, 283, 296, 339, 300, 228, 262, 330, 357, 371, 384, 378, 372 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,2

COMMENTS

As difference of two odd primes, all terms of A230481(n)=prime(prime(2n)-prime(2 prime(n)) are even, which motivates to define the present sequence.

Further values: a(100)=617, a(10^3)=9344, a(10^4)=114171, a(10^5)=1325772, a(10^6)=14979156; a(10^10)~2.2*10^11, a(10^20)~3.9*10^21, a(10^30)~5.5*10^31.

LINKS

M. F. Hasler, Table of n, a(n) for n = 1..10000

FORMULA

a(n) = (A217622(n) - A230460(n))/2.

PROG

(PARI) a=n->(prime(prime(2*n)-prime(2*prime(n)))/2

CROSSREFS

Cf. A066066, A000040, A006450, A031215, A217622, A230460.

Sequence in context: A242336 A285312 A065154 * A263546 A143408 A191331

Adjacent sequences:  A230479 A230480 A230481 * A230483 A230484 A230485

KEYWORD

sign

AUTHOR

M. F. Hasler, Oct 20 2013

STATUS

approved

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Last modified January 26 12:00 EST 2022. Contains 350598 sequences. (Running on oeis4.)