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 A140292 a(n) is a square mod a(n-1), a(n) > a(n-1) and a(n) semiprime. 1
 4, 9, 10, 14, 15, 21, 22, 25, 26, 35, 39, 49, 51, 55, 69, 82, 86, 87, 91, 95, 106, 115, 119, 121, 122, 123, 133, 134, 143, 146, 155, 159, 166, 169, 178, 183, 187, 202, 203, 219, 235, 249, 253, 254, 262, 265, 274, 278, 287, 289, 291, 295, 299, 302, 303, 309, 327 (list; graph; refs; listen; history; text; internal format)
 OFFSET 1,1 LINKS FORMULA a(n+1) = MIN{k>a(n) and a(n) is a quadratic residue of a(n+1) and a(n+1) is in A001358}. MAPLE isqResid := proc(n, modp) local x ; for x from 1 to floor(modp/2) do if x^2 mod modp = n mod modp then RETURN(true) ; fi ; od: RETURN(false) ; end: isA001358 := proc(n) RETURN( numtheory[bigomega](n)= 2) ; end: A140292 := proc(n) option remember ; local a; if n = 1 then 4; else for a from A140292(n-1)+1 do if isA001358(a) and isqResid(a, A140292(n-1)) then RETURN(a) ; fi ; od ; fi ; end: seq(A140292(n), n=1..80) ; - R. J. Mathar, May 31 2008 CROSSREFS Cf. A001358, A034794, A088190. Sequence in context: A178241 A028839 A141833 * A208980 A010426 A054294 Adjacent sequences:  A140289 A140290 A140291 * A140293 A140294 A140295 KEYWORD easy,nonn AUTHOR Jonathan Vos Post, May 24 2008 EXTENSIONS Corrected and extended by R. J. Mathar, May 31 2008 STATUS approved

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