A128278 an=n-th smallest integer m=p1*p2*p3, product of 3 odd primes such that d+2m/d are all primes for d dividing 2m.

105, 165, 231, 935, 2109, 2795, 3021, 3819, 6981, 7205, 11285, 12341, 13101, 16419, 17549, 19839, 21749, 21995, 26391, 31229, 31269, 46631, 62651, 63645, 65391, 76155, 77585, 100955, 110811, 113555, 118031, 136451, 148359, 150245, 154679

Offset: 1

Author

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

Keywords

• nonn

Examples

			E.g. 105=3.5.7, 2.3.5.7+1=211, 2+3.5.7=107, 3+2.5.7=73, 5+2.3.7=47, 7+2.3.5=37, 2.3+5.7=41, 2.5+3.7=31, 2.7+3.5=29 are all primes and 3.5.7 is the smallest such number, so a(1)=105.
		

Crossrefs

Cf. A128276, A128277, A128279, A045536.