

A062353


Primes of the form bbbbba... where a and b are digits.


3



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, 113, 223, 227, 229, 331, 337, 443, 449, 557, 661, 773, 881, 883, 887, 991, 997, 1117, 2221, 3331, 4441, 4447, 5557, 6661, 8887, 11113, 11117, 11119, 22229
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OFFSET

1,1


COMMENTS

Number of terms of n digits: 4, 21, 16, 8, 9, 8, 2, 8, 7, 3, 4, 5, 2, 2, 4, 0, 3, 4, 2, 3, 2, 2, 4, 1, 0, ..., .  Robert G. Wilson v, May 29 2011


LINKS

Charles R Greathouse IV, Table of n, a(n) for n = 1..260


EXAMPLE

4441 is a member where a=1 and b = 4.


MATHEMATICA

f[n_] := Select[ Union@ Flatten@ Table[ FromDigits@ Join[ Table[b, {n  1}], {a}], {b, 9}, {a, {1, 3, 7, 9}}], PrimeQ]; f[1] = {2, 3, 5, 7}; Array[f, 5] // Flatten (* Robert G. Wilson v, May 29 2011 *)


PROG

(PARI) print1("2, 3, 5, 7"); for(n=2, 20, forstep(k=10^n\91, 10^n9, 10^n\91, for(m=k+1, k+9, if(isprime(m), print1(", "m))))) \\ Charles R Greathouse IV, May 29 2011


CROSSREFS

Cf. A061022.
Sequence in context: A038618 A030475 A069676 * A077390 A069677 A069678
Adjacent sequences: A062350 A062351 A062352 * A062354 A062355 A062356


KEYWORD

nonn,base,easy


AUTHOR

Amarnath Murthy, Jun 23 2001


EXTENSIONS

More terms from Jason Earls, Jun 26 2001
Corrected and extended by Dean Hickerson, Jul 10 2001


STATUS

approved



