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A061022
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Primes of the form abbbbb... where a and b are digits.
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2
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2, 3, 5, 7, 11, 13, 17, 19, 23, 29, 31, 37, 41, 43, 47, 53, 59, 61, 67, 71, 73, 79, 83, 89, 97, 199, 211, 233, 277, 311, 433, 499, 577, 599, 677, 733, 811, 877, 911, 977, 1777, 1999, 2111, 2333, 2777, 2999, 4111, 4999, 5333, 7333, 8111, 8999, 23333, 47777
(list; graph; refs; listen; history; internal format)
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OFFSET
| 1,1
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COMMENTS
| Number of terms of n digits: 4, 21, 15, 12, 7, 8, 2, 7, 2, 3, 5, 2, 2, 7, 2, 4, 2, 2, 4, 3, 1, 0, 3, 3, 0, ..., . Robert G. Wilson v, May 29 2011.
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LINKS
| Harry J. Smith, Table of n, a(n) for n=1,...,79
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EXAMPLE
| 4111 is a member where a=4 and b = 1.
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MATHEMATICA
| f[n_] := Select[ Union@ Flatten@ Table[ FromDigits@ Join[{a}, Table[b, {n - 1}]], {a, 9}, {b, {1, 3, 7, 9}}], PrimeQ]; Array[f, 5] // Flatten (* Robert G. Wilson v, May 29 2011 *)
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PROG
| (PARI) { n=r=0; default(primelimit, 1777777777); forprime (p=2, 1777777777, if (p>100, r=p\10; d=p-r*10; while (r>9 && r-r\10*10 == d, r\=10)); if (r<=9, write("b061022.txt", n++, " ", p)) ) } [From Harry J. Smith (hjsmithh(AT)sbcglobal.net), Jul 16 2009]
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CROSSREFS
| Cf. A062353.
Sequence in context: A069682 A069683 A069684 * A079152 A124590 A049573
Adjacent sequences: A061019 A061020 A061021 * A061023 A061024 A061025
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KEYWORD
| nonn,base,easy
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AUTHOR
| Amarnath Murthy (amarnath_murthy(AT)yahoo.com), Jun 23 2001
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EXTENSIONS
| Corrected and extended by Dean Hickerson (dean.hickerson(AT)yahoo.com), Jul 10, 2001
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