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 A090152 Primes of the form identical digits preceded by a 4. 2
 41, 43, 47, 433, 499, 4111, 4999, 47777, 49999, 4999999, 41111111111111, 47777777777777, 499999999999999, 43333333333333333, 41111111111111111111111111, 47777777777777777777777777 (list; graph; refs; listen; history; text; internal format)
 OFFSET 1,1 LINKS Vincenzo Librandi, Table of n, a(n) for n = 1..36 MATHEMATICA Select[ FromDigits /@ Flatten[ Table[ PadRight[{4}, i, # ] & /@ {1, 2, 3, 4, 5, 6, 7, 8, 9}, {i, 2, 24}], 1], PrimeQ[ # ] &] Select[Flatten[Table[FromDigits[PadRight[{4}, n, k]], {n, 2, 30}, {k, {1, 3, 7, 9}}]], PrimeQ] (* Harvey P. Dale, Apr 23 2019 *) CROSSREFS Sequence in context: A062669 A284290 A045710 * A139774 A007643 A259552 Adjacent sequences: A090149 A090150 A090151 * A090153 A090154 A090155 KEYWORD nonn,base AUTHOR Robert G. Wilson v, Nov 22 2003 STATUS approved

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Last modified June 24 02:53 EDT 2024. Contains 373661 sequences. (Running on oeis4.)