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 A154367 Numbers k such that the sum of the prime factors of composite(k) (with multiplicity) is prime and lpf(composite(k)) + gpf(composite(k)) is composite. 0
 18, 30, 36, 39, 44, 53, 54, 73, 76, 86, 112, 113, 116, 126, 132, 134, 141, 160, 163, 175, 191, 194, 197, 211, 214, 219, 231, 233, 250, 258, 265, 276, 279, 294, 295, 301, 308, 311, 312, 320, 325, 331, 333, 335, 338, 340, 341, 350, 351, 361, 376, 383, 385, 394 (list; graph; refs; listen; history; text; internal format)
 OFFSET 1,1 LINKS EXAMPLE 18 is a term because composite(18) = 28 = 2*2*7, 2 + 2 + 7 = 11 is prime, and 2 + 7 = 9 is composite. 30 is a term because composite(30) = 45 = 3*3*5, 3 + 3 + 5 = 11 is prime, and 3 + 5 = 8 is composite. MAPLE isA002808 := proc(n) n >= 4 and not isprime(n) ; end proc: A046343 := proc(n) pss(A002808(n)) ; end proc: A020639 := proc(n) numtheory[factorset](n) ; min(op(%)) ; end proc: A006530 := proc(n) numtheory[factorset](n) ; max(op(%)) ; end proc: for n from 1 to 500 do if isprime(A046343(n)) and isA002808( A020639(A002808(n)) + A006530(A002808(n)) ) then printf("%d, ", n) ; end if; end do: # R. J. Mathar, May 05 2010 CROSSREFS Cf. A000040 (primes), A002808 (composites). Sequence in context: A259635 A032612 A151700 * A161164 A092357 A141115 Adjacent sequences:  A154364 A154365 A154366 * A154368 A154369 A154370 KEYWORD nonn AUTHOR Juri-Stepan Gerasimov, Jan 08 2009 EXTENSIONS Corrected (44 inserted, 120 removed, 146 removed) and extended by R. J. Mathar, May 05 2010 Name and Example section edited by Jon E. Schoenfield, Feb 11 2019 STATUS approved

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Last modified October 15 20:04 EDT 2019. Contains 328037 sequences. (Running on oeis4.)