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 A180344 Four-digit semiprimes that are concatenation and product of two 2-digit primes. 1
 1147, 1159, 1189, 1343, 1711, 1943, 1961, 2911, 2923, 3713, 4171, 4183, 4189, 4307, 4331, 4717, 5329, 5917 (list; graph; refs; listen; history; text; internal format)
 OFFSET 1,1 COMMENTS There are 18 such integers: 1147=31*37,1159=19*61,1189=29*41,1343=17*79,1711=29*59,1943=29*67, 1961=37*53,2911=41*71,2923=37*79,3713=47*79,4171=43*97,4183=47*89, 4189=59*71,4307=59*73,4331=61*71,4717=53*89,5329=73*73,5917=61*97. Two particularly interesting cases: 1159=19*61=> 1961=37*53, 2911=41*71 =>4171=43*97. LINKS EXAMPLE 1147 = concatenation of primes 11 and 47 and product of primes 31 and 37. CROSSREFS Sequence in context: A227478 A190924 A196779 * A031785 A274297 A074255 Adjacent sequences: A180341 A180342 A180343 * A180345 A180346 A180347 KEYWORD base,fini,full,nonn AUTHOR Zak Seidov, Jan 18 2011 STATUS approved

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Last modified January 31 01:17 EST 2023. Contains 359947 sequences. (Running on oeis4.)