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A201966 Primes of the form identical digits preceded by an 11. 1
11, 113, 11777, 1133333, 1199999, 113333333, 11777777777, 1111111111111111111, 11111111111111111111111, 1177777777777777777777777, 113333333333333333333333333, 1177777777777777777777777777777777777777777777777 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

LINKS

Vincenzo Librandi, Table of n, a(n) for n = 1..16

MATHEMATICA

Select[FromDigits/@Flatten[Table[PadRight[{11}, i, #]&/@{1, 2, 3, 4, 5, 6, 7, 8, 9}, {i, 2, 1200}], 1], PrimeQ[#]&]

CROSSREFS

Sequence in context: A048553 A110799 A088089 * A121196 A251261 A332729

Adjacent sequences:  A201963 A201964 A201965 * A201967 A201968 A201969

KEYWORD

nonn,base,less

AUTHOR

Vincenzo Librandi, Dec 10 2011

STATUS

approved

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Last modified August 9 13:57 EDT 2020. Contains 336323 sequences. (Running on oeis4.)