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 A034820 Concatenations C1 and C2 and C3 and C4 are all prime (see the comment lines). 1
 16776, 41719, 164612, 188435, 188682, 312184, 317594, 392771, 397617, 450413, 476055, 486283, 492240, 497913, 539471, 584029, 620029, 640883, 648445, 656757, 903009, 992790, 993475, 995917, 1045387, 1082078, 1194606, 1252496, 1322841 (list; graph; refs; listen; history; text; internal format)
 OFFSET 0,1 COMMENTS C1 = 'prevprime(n) followed by n followed by prevprime(n)' C2 = 'prevprime(n) followed by n followed by nextprime(n)' C3 = 'nextprime(n) followed by n followed by prevprime(n)' C4 = 'nextprime(n) followed by n followed by nextprime(n)' LINKS EXAMPLE n=41719 -> next prime is 41729, previous prime is 41687, thus '416874171941687' and '416874171941729' and '417294171941687' and '417294171941729' are all four primes. CROSSREFS Cf. A034808-A034821. Sequence in context: A052190 A068784 A183844 * A053074 A115923 A243836 Adjacent sequences: A034817 A034818 A034819 * A034821 A034822 A034823 KEYWORD nonn,base AUTHOR Patrick De Geest, Oct 15 1998 STATUS approved

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Last modified December 1 17:49 EST 2022. Contains 358475 sequences. (Running on oeis4.)