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A128279 an=n-th smallest integer of the form m=p1*p2 where pi are odd primes such that d+2m/d are all primes for d dividing 2m. 2
15, 21, 35, 39, 51, 65, 95, 155, 221, 329, 371, 485, 519, 611, 905, 989, 1121, 1199, 1469, 1509, 1541, 1661, 1821, 3039, 3189, 3431, 3641, 3791, 4055, 4109, 4281, 4601, 4859, 5079, 5111, 5195, 5331, 5429, 5579, 5951, 5979, 6161, 6245, 6731, 6881, 7415 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

LINKS

Table of n, a(n) for n=1..46.

EXAMPLE

E.g. 35=5.7, 2.5.7+1=71, 2.5+7=17, 2.7+5=19. 5.7+2=37 are all primes and this is the 3rd such number, so a(3)=35

CROSSREFS

Cf. A128276, A128277, A128278, A045536.

Sequence in context: A123912 A296244 A225916 * A099611 A081934 A095147

Adjacent sequences:  A128276 A128277 A128278 * A128280 A128281 A128282

KEYWORD

nonn

AUTHOR

Kok Seng Chua (chuakokseng(AT)hotmail.com), Mar 05 2007

STATUS

approved

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Last modified February 19 18:22 EST 2019. Contains 320327 sequences. (Running on oeis4.)