This site is supported by donations to The OEIS Foundation.

 Hints (Greetings from The On-Line Encyclopedia of Integer Sequences!)
 A107707 3-almost primes whose prime factors sum to a prime. 3
 12, 28, 45, 52, 63, 75, 76, 99, 117, 147, 148, 153, 165, 172, 175, 207, 245, 268, 273, 279, 316, 325, 333, 345, 369, 385, 388, 399, 412, 423, 435, 436, 475, 477, 507, 508, 549, 561, 595, 603, 651, 652, 657, 665, 715, 747, 759, 772, 775, 777, 795, 833, 845 (list; graph; refs; listen; history; text; internal format)
 OFFSET 1,1 LINKS EXAMPLE a(5) = 63 = 3*3*7 because 3+3+7 = 13 is prime. MATHEMATICA Select[Range[1000], PrimeOmega[#]==3&&PrimeQ[Total[ Times@@@ FactorInteger[ #]]]&] (* From Harvey P. Dale, Nov 10 2011 *) CROSSREFS Sequence in context: A098502 A158953 A223454 * A183053 A126195 A164533 Adjacent sequences:  A107704 A107705 A107706 * A107708 A107709 A107710 KEYWORD easy,nonn AUTHOR Giovanni Teofilatto, Jun 10 2005 EXTENSIONS Corrected and extended by Ray Chandler, Jun 12 2005 STATUS approved

Lookup | Welcome | Wiki | Register | Music | Plot 2 | Demos | Index | Browse | More | WebCam
Contribute new seq. or comment | Format | Transforms | Puzzles | Hot | Classics
Recent Additions | More pages | Superseeker | Maintained by The OEIS Foundation Inc.

Content is available under The OEIS End-User License Agreement .