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 A109357 Numbers k such that the string 112354k is prime. 1
 1, 21, 73, 81, 127, 157, 159, 181, 211, 213, 217, 259, 267, 271, 273, 283, 289, 301, 303, 321, 327, 337, 369, 409, 423, 457, 477, 507, 523, 537, 553, 559, 597, 603, 621, 631, 651, 691, 699, 727, 799, 807, 817, 843, 849, 867, 877, 897, 909, 919, 927, 967, 969, 981, 993, 997, 1017, 1021, 1047 (list; graph; refs; listen; history; text; internal format)
 OFFSET 1,2 LINKS Michael De Vlieger, Table of n, a(n) for n = 1..10000 EXAMPLE If k=1 then 112354k = 1123541 (prime). If k=213 then 112354k = 112354213 (prime). MATHEMATICA Select[Range[1050], PrimeQ[112354*10^IntegerLength[#] + #] &] (* Michael De Vlieger, Jan 22 2018 *) PROG (MAGMA) [ n: n in [1..1750] | IsPrime(Seqint(Intseq(n) cat [4, 5, 3, 2, 1, 1])) ]; // Vincenzo Librandi, Feb 02 2011 CROSSREFS Sequence in context: A156285 A160435 A240824 * A283802 A082041 A316887 Adjacent sequences:  A109354 A109355 A109356 * A109358 A109359 A109360 KEYWORD nonn,base AUTHOR Parthasarathy Nambi, Aug 22 2005 EXTENSIONS More terms from Vincenzo Librandi, Feb 02 2011 STATUS approved

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Last modified February 21 04:18 EST 2019. Contains 320371 sequences. (Running on oeis4.)