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 A169605 Numbers x of the form x = 2*y - 3 = 3*z - 2 where y and z are primes. 1
 7, 19, 31, 55, 91, 139, 175, 199, 211, 379, 391, 451, 499, 535, 631, 715, 919, 931, 1039, 1135, 1291, 1315, 1399, 1435, 1639, 1711, 1759, 1819, 1855, 1891, 1939, 2179, 2215, 2359, 2431, 2515, 2575, 2719, 2731, 2899, 2971, 3115, 3271, 3691, 3775, 3955, 4195 (list; graph; refs; listen; history; text; internal format)
 OFFSET 1,1 LINKS EXAMPLE a(1)=7 because 5*2 - 3 = 3*3 - 2; a(2)=19 because 11*2 - 3 = 7*3 - 2. MAPLE isA169605 := proc(x) if type(x+3, 'even') then if (x+2) mod 3 = 0 then isprime( (x+3)/2) and isprime((x+2)/3) ; else false ; end if else false; end if; end proc: for x from 1 to 10000 do if isA169605(x) then printf("%d, ", x) ; end if; end do: # R. J. Mathar, Jan 27 2010 MATHEMATICA Select[3Prime[Range[250]]-2, PrimeQ[(3+#)/2]&] (* Harvey P. Dale, May 11 2011 *) PROG (Sage) is_prime_Q = lambda x: x.is_integral() and Integer(x).is_prime() A169605 = list(x for x in range(1, 10**4) if is_prime_Q((x+3)/2) and is_prime_Q((x+2)/3)) A169605[:36] # D. S. McNeil, Dec 21 2009 CROSSREFS Cf. A000040, A131426. Sequence in context: A114564 A191118 A298019 * A216532 A249375 A212492 Adjacent sequences:  A169602 A169603 A169604 * A169606 A169607 A169608 KEYWORD nonn AUTHOR Juri-Stepan Gerasimov, Dec 03 2009 EXTENSIONS Corrected and extended by Jim Nastos and D. S. McNeil, Dec 21 2009 A few more terms from R. J. Mathar, Jan 27 2010 STATUS approved

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Last modified June 13 00:57 EDT 2021. Contains 344980 sequences. (Running on oeis4.)